* ArcFatigue:
** There were several areas that were thought to be too long, or pointless, to traverse to get to the main objectives that it was considered boring for some players. As a result, the 2.0 patch went about updating the game world to reduce such fatigue. Some of the changes included:
*** Act 1: Reducing the Submerged Passage from 2 levels to 1. Deleting the Coves area between the Ship Graveyard and Merveil's home.
*** Act 2: Reducing the Chamber of Sins from 3 levels to 2. Deleting the Blackwood area between the Riverways and Western Forest. Reducing the Vaal Ruins from 2 levels to 1. Reducing the Caverns from 2 levels to 1.
*** Act 3: Deleting the Sewer Waterway area between the Warehouse Sewers and Ebony Barracks. Reducing the Lunaris Temple from 3 levels to 2.
** The Act 2 quest to kill off the three Bandit Lords was considered to be annoying because you couldn't reach the northern Bandit Lord, Oak, until the Exile made his/her way through the Vaal Ruins, which was blocked off from entering until the Loratta tree blocking the entrance was killed. But in order to kill Loratta, the player had to journey to the Chamber of Sin and Weaver Spider home first to collect items needed to kill said tree. The 2.0 patch fixed this by moving the Wetlands zone with Oak in it to come before the Vaal Ruins instead of after it. Another noticeable change for this quest was getting rid of the Blackwood zone so that the journey to the western Bandit Lord, Alira, would be a bit shorter.
* SugarWiki/AwesomeMusic: Quite a lot, actually ! The Solaris Temple music in particular is very popular.
* BreatherLevel: Act 1 of Cruel difficulty. Yes, the monsters have their health and damage scaled up, but they're still mostly the same shambling pushovers that they were before, as opposed to the fast moving, hard hitting, projectile spamming DemonicSpiders that you've been dealing with throughout Normal Act 4. Going from Cruel Act 4 to Merciless Act 1 involves a similar difficulty drop.
* BrokenBase:
** The orb market, either it's a great replacement over using gold, or it's too complicated and grindy.
** The developer's ah, ''controversial'' decision to stick with non-instanced loot.
*** Now that they've implemented an option for permanently allocated loot, it's more broken between StopHavingFunGuys who think that free-for-all loot should be the only way to play and that the developers shouldn't have added the option, and everyone else who just plays with the option they prefer.
** The skill-tree has always been a split between those that love it for players being able to control how to evolve their character, and those who think that the skill-tree is too simple and lopsided towards certain builds to bring any depth or creativity to the game. A prime example being when a player works around the skill-tree to pile up on the skill points that increase health over experimenting with any of the other skills, because piling up on health is considered to be one of the more powerful builds in the end-game.
*** The overly powerful health is averted nowadays, because other means of defense have been buffed. A somewhat solid reserve of HP is still considered to be very helpful though.
** Getting rid of Act 3's Sewer Waterway in the 2.0 patch. For some, people are glad that it was cut since there was already so much sewer content to deal with that the amount of sewer zones to go through just got tiresome after awhile. On the other hand, the loss of the Sewer Waterway is felt to be a loss of some game immersion as it was a journey to travel under the river to get to the Ebony Barracks. As a result, the new sewer entrance to the Barracks being just shortly after the Warehouse Sewer's Undying Wall has been felt to be a tad out-of-place.
** Come the 3.0 patch, the massive nerfing to Energy Shield builds has also raised some heckles.
* CompleteMonster:
** [[BigBad High Templar Dominus]] is the master of the Templar Order, TheEmperor of the theocratic nation of Oriath, and the ArchEnemy of the [[PlayerCharacter Exiles]] as a whole. Dominus runs a corrupt regime in Oriath where he uses threats of torture, execution, and exile to keep the population under control as he conducts his experiments in thaumaturgy (miracle working). In an effort to [[ImmortalityImmorality seek immortality]], he masterminded the experimentation of slaves and criminals which most often resulted in an excruciating death or all manner of BodyHorror on survivors. In order to make his experiments run faster and more efficiently, he moved his operations to the continent of Wraeclast and exiled many innocent people there to be used in the experiments en masse, if they weren't killed by the local wildlife or undead first. [[AllCrimesAreEqual Oriathan citizens were exiled with the likes of serial killers and rapists]] for crimes such as speaking out against the Templars, running businesses without a license, or even simply being homeless. As his skills in thaumaturgy improved, Dominus's goals expanded to infusing those loyal to him with virtues gems in order to make a perfect race for him to rule over as their immortal GodEmperor. As his experiments reached their climax, Dominus had thousands of slaves imported from Oriath to be twisted into abominations and become his servants, or be tossed aside into oceans of blood and mountains of corpses if they didn't survive.
** [[GreaterScopeVillain Malachai, the Nightmare]], is the greatest thaumaturgist who ever lived and the being responsible for all the horrors that infest the haunted continent of Wraeclast. Malachai was once the right hand of Emperor Chitus of the Eternal Empire and the lead thaumaturgist for the Empire. With Malachai's skill, he was able to successfully implant virtue gems into the aristocracy and make them immortal and into the soldiers to make them powerful warriors. [[AmbitionIsEvil Ever seeking to expand his skill]], Malachai experimented on slaves and, to Chitus's reluctance, the lower class. This lead to the Purity Rebellion under the Templar Voll who slew Chitus, but spared Malachai as he made Voll a promise he couldn't refuse. Malachai promised to kill the Beast, the source of thaumaturgy, but had plans of his own. He manipulated Dialla, the former consort of Chitus, into loving him and life and sought to sacrifice her to power a device to kill the Beast. As Malachai planned, she didn't want to die and the device only succeeded in opening a way to the Beast. Malachai took control of the Beast and used its godlike power to create his own kingdom: his [[{{Dystopia}} perfect world of nightmare]]. In a single day, Malachai destroyed the Eternal Empire and corrupted Wraeclast by driving everyone and everything on the continent insane with horrible nightmares, and further hunted the survivors by resurrecting anyone who died into undeath. Sealed away by survivors, Malachai captured the souls of great heroes such as Koam of the Karui, arena champion Daresso, and even his enemy Voll and used their tortured spirits to plan his release. In the present day, Malachai sought to escape his prison and spread his eternal nightmare to the entire world.
* DemonicSpiders: Rogue Exiles are hostile [=NPCs=] that are exiles like you and have a chance to spawn pretty much anywhere. They have access to the same skills as you do and can be very dangerous, especially in the higher difficulty levels. Bumping into one unprepared can lead to a swift death.
** There are a few monster mods that can down players quickly. For example, Corrupted Blood inflicts the bleed status effect and can sap your health in seconds unless you have a flask with a remove bleed effect on hand. Monsters with Reflect Elemental Damage can also be a huge pain for casters relying on elemental spells. Piling on a load of Storm Calls or fully charging a Flame Blast can lead to an OhCrap moment when you discover that the monster you're about to nuke is going to reflect that right back at you.
** With the introduction of the talisman league, which spawned monsters holding the aformentioned talisman, giving them a unique effect and rewarding the player with one if they managed to kill it, one particular type quickly gained infamy to the point of getting nerfed: Bonespire. Monsters holding the Bonespire talisman sporadically created spiky areas on the floor which both damaged and applied a stacking dot that can't be removed like bleed or circumvented like puncture. Problem was the damage was way too high, to the point of even the slightes of delayed reactions meant certain death and even then portaling back to town was the only real counter to its stacking dot. This was quickly nerfed in a patch, almost not even a day after the league started.
** Monster packs with Bloodline mods can be horrifically dangerous. Bearers of the Guardian causes the pack to summon an Animated Guardian that cannot be killed until the pack is exterminated. Voidspawn of Abaxoth summons a BonusBoss unique demon when the last pack member is killed. Heralds of the Obelisk leave behind lightning-spell spamming untargetable obelisks until the last member of the pack is killed. Frost and Storm Bearers get an honorable mention, as each one spawns a circular AoE that explodes a few seconds after killing them, doing respectable damage. Easy to avoid... if you can see where the circles are, which is not possible on some maps.
** The DemonicSpiders factor can be compounded by enemies with multiple modifiers. A rare monster with a Nemesis mod, possessed by a Tormented Spirit, and bearing multiple Essences will probably drop some nice loot, but fighting it is going to be a real bad time.
** The Harbinger league throws the titular Harbingers at you: EnemySummoner foes who are invincible on their own and spam devastating spells at the player. The only way to kill them is to slay their minions, as each dead minion drains a little more of their health. Unfortunately, the minions are also powerfully-buffed as well. Rounding a corner and coming face to face with a glowing blue Harbinger and it's backup turns a normal dungeon run into a surprise round of desperate kiting and minion-slaying against an enemy just as dangerous as most bosses.
* DuelingGames: With Diablo 3 (and perhaps Torchlight 2) as the prime action-rpg of this time-period. Marvel Heroes is sometimes brought into the conversation as well. More recently with ''VideoGame/GrimDawn''.
* EarlyBirdBoss: Most sub-bosses in Act 1 on normal difficulty, primarily Hailrake (see below).
* GameBreaker: The game has had a few of them over the years. Many many different types of builds can be very powerful with the right gear and skills, but some have been so obscenely powerful that they've shaped the meta for years at a time on occasion.
** Before patch 3.0, Energy Shield was the dominant defensive setup in the game for a very long time simply because of how quickly it could scale with gear, to the point where it was possible to gain so much Energy Shield as to make characters functionally invincible
** Patch 3.0 massively buffed Vaal Pact, turning it into a must-have for most melee builds thanks the sheer amount of life leech it gives you - Marauders especially benefit from it thanks to their Ascendancies like Cloaked In Savagery, which has excellent synergy with Vaal Pact. This gets even more ridiculous when combined with the also-buffed Mind Over Matter node, which makes 30% of the damage you take drain your mana instead of health. It was eventually nerfed in patch 3.1.
** Well-built summoner builds are this in some players eyes. Since minions are completely automated, they allow the player to focus on avoiding damage which makes surviving the bosses much easier. This also means that Reflect, one of the most dreaded effects in the game, is utterly useless against a minion summoner. Several Witch Necromancer Ascendancy nodes - in particular Mistress of Sacrifice, which allows your Offering gems to apply to you as well as minions - make them even stronger and faster. However, minion builds are often finicky in actual game play, difficult to gear properly due to the mechanics of the spells, and often considered boring due to the passiveness of the gameplay, so summoner builds are relatively rare and their status as game-breaking debatable.
** Also with summoners, the new acts introduced in ''The Fall of Oriath'' also added new enemies. Of particular note are the Tukohama's Vanguards[[note]]Act 6, which drop extremely damaging Scorching Ray totems[[/note]], Solar Guards[[note]]Act 8, which throw multiple fireballs in an arc[[/note]], Frost Sentinels[[note]]Also Act 8, which are the same as the DiscOneNuke Fire Sentinels in Act 3 except they can freeze enemies too[[/note]] and Wicker Men [[note]]Act 10, which have a spell similar to Righteous Fire that burns enemies around them[[/note]]. They're all DemonicSpiders when you fight them, but for summoner builds, these enemies are incredibly powerful as Spectres with proper Spectre gear[[note]]Bones of Ullr, Vis Mortis, Victario's Charity/Tukohama's Fortress (for Vanguards), + minion helmets[[/note]], capable of utterly melting endgame bosses like the Guardians while the player runs around like ''Sonic the Hedgehog'' thanks to Flesh Offering and tanking huge damage thanks to minion passive nodes/Bone Offering. It's one of the primary reasons why the Necromancer is by far the most popular Witch Ascendancy.
*** Before then, the Act 4 Stygian Revanants and the aforementioned Fire Sentinels were this as well.
** Tabula Rasa is both this and/or a DiscOneNuke depending on your build. Tabula is a white chest armour piece that has six-linked gem slots and has no level requirement, with the tradeoff that it also has no stats on it whatsoever. This is ludicrously powerful, since most of your damage comes from support gems linked to attack gems, making it easily the best leveling item in the game - to the point where it can take some builds all the way to the endgame.
* HeartwarmingMoments: For all the chaos they're causing with the war against Solaris, the Lunaris Cultists in Act 8 seem to be attempting to give proper burials to the victims of Piety's death camp from Act 3.
* HolyShitQuotient: The typical reaction when someone sees this game's skill tree for the first time. Fans call it a skill ''forest'' for a reason!
* MemeticMutation:
** "Skillgrimage."
** Vagan's greeting, "Let me bend your ear for a moment!". Helps that it's [[{{Mondegreen}} easy to mishear as]] "Let me bend your ''rear'' a moment," and Vagan is [[CasanovaWannabe the kind of guy]] who would probably think that's a suave come-on.
** "Where there is a [adjective] key, there must be a [adjective] door."[[labelnote:Explanation]]Whenever the player picks up a key in the Labyrinth, Izaro will chime in with some form of the above line. Fans quickly latched on to the line's exploitability and CaptainObvious nature.[[/labelnote]]
** "WE TOUHOU NOW LADS!" [[labelnote:Explanation]]From the ''Atlas of Worlds'' expansion onwards a lot of new boss fights have involved BulletHell - style attacks and stage hazards. [[/labelnote]]
* MoralEventHorizon: Given what you see of the results of Piety's... "experiments" inside the Lunaris Temple, she'd crossed this point long ago.
* ScrappyMechanic: After completing the main story content, you lose 10% of your experience towards the next level every single time you die. This makes trying to level up in the map system especially painful as enemies gradually get to the point where they can easily kill you if you get stun-locked (which is often), so an unlucky death can potentially set you back ''days''. Getting to level 90 is nearly impossible for most builds, let alone past 80 or so.
* ThatOneAchievement: All Ears. This achievement requires you to, on one character, hear every optional line of dialogue in the game. Not only can you [[PermanentlyMissableContent screw this up]] within ten minutes of making the character, but it requires you to take an [[GuideDangIt extremely specific set of nonsensical actions]] in Act 2 across all three difficulties that require a rather expensive item to finish. A guide of who to talk to, at what time, and in what conditions is mandatory due to the extremely limited time windows of some dialogue choices.
* ThatOneBoss: Many, often different for each character-build.
** Oak in Act 2's bandit quest. He's incredibly strong, and he has a leap attack that instantly sends him to his target. This leap attack has almost no cooldown either, so expect to see him leaping around like a rabbit the entire fight. He's even harder to deal with if you like using a lot of fire skills. Expect to find yourself joining random parties just to deal with him.
** Merveil, the end boss of Act 1, is this for some players, especially those who are new to the game. At first, it seems like she just attacks the player with many powerful [[AnIcePerson frost-based]] magic attacks, but upon defeating her, her ''true'' form appears and she not only completely regenerates her health, but also becomes a [[TheMinionMaster summoner-type]] boss (alongside being an ice-mage) that will endlessly spawn {{Mooks}} to [[GodDamnedBats constantly annoy you]]; some even being suicidal-bomber types which will instantly destroy a chunk of health if the player let even one get too close. To top it all off, she has a shield that will regenerate if players hold off on attacking for too long, and in the second fight against a summoner-ice-mage, expect it to happen A LOT. Long story short, players are in for a long, drawn-out, fight against Merveil if they're not stocked up on cold-resist, or they're short on any area-of-effect type attacks to keep the summoned pets at bay.
** Hailrake is brutal in both normal and merciless difficulties. In normal you fight him at about level 2 when you have no real gear, skills, or passive points and you're just getting the hang of the game. His primary ability is both extremely powerful and fairly counter-intuitive if you don't already know what it does (at short range it's harder to dodge, but at long range it's 7 times more likely to completely freeze you which is more or less a guaranteed kill at this level). On merciless you know what to expect, but the map he's on is level 58 and directly adjacent to level 53 maps with no warning that's the case. He is in fact higher level than the mid act boss Brutus and about the same as the end act boss Merveil.
** Players disappointed with Piety's relative ease have had [[BeCarefulWhatYouWishFor complaints answered]] with High Templar Dominus. BossRush as first ''and'' second phases, FlunkyBoss while being no slouch himself in third and fourth, and in said fourth phase, he can call a bloody death mist that instantly kills you unless you stand ''right next to him'' and his powerful melee attacks.
** Your first fight with Piety in the city ruins. She spams a spell (Chain Lightning) that causes a huge ball of energy to careen across the screen firing thunderbolts at anything nearby. If you have low lightning resistance, she's a nightmare.
** Piety in Act 4 is brutal for new players and the archenemy of any minion-dependent class. Still has all the things that make her frustrating in earlier acts, but she gains 6 assisting enemies that activate over time and begin spawning huge numbers of adds unless killed immediately. Further she gains a new lightning beam attack that sweeps the entire area, does enormous amounts of damage, and has no safe place to hide from it. You're meant to keep running in circles around her while she uses it, which often stops you from attacking (letting her energy shield regenerate) and ''will'' kill all your summons, spectres, and totems. And sometimes she'll be next to a wall when she does it so you can't run behind her either, requiring you to jump the beam with a dash. What really makes her a bane though is that, because of the level design and mechanics, you have to fight her every time you go through the area and, unlike most major bosses, the next waypoint is ''not'' by the start of the next area but in the ''middle'' of it, requiring a good slog through one of the game's tougher areas just to find it. Until you do, you're not done with Piety.
** The BonusDungeon carrion-beetle boss, the Sunburst Queen. Powerful fire-spells coupled with the the Queen's never-ending spawning of 50 to 100 suicidal-bombing carrion beetles makes for a rather difficult fight. It's almost like dealing with a fire-version of Merveil...[[UpToEleven only a hundred times worse]]!
** With the introduction of Act 4, another slew of tricky unique monsters also followed. While most areas are tricky, but manageable, people come to dread a certain area because of its uniques alone: Kaom's Dream segment.
*** The first area has Torchoak Grove, a unique totem enemy accompanied by other totems. All of them can bombard the player with mortar-like projectiles which outrange practically any ranged attack at this point, being able to hit from over a full screen away, and way too high damage per projectile compared to the area, usually one-shotting unwary players unfortunate enough to get caught in too many of the blasts. It was later revealed that the high amount of damage was a bug and was fixed in patch 2.1, making them a lot more manageable.
*** The second area has Triskeriaki, a unique rakango enemy with the ability to spawn three tentacles to fire a volley of spikes instead of just one like the regular version. One volley is bad enough, although survivable with sufficient defense, but if you get caught in the crossfire of two or, heaven forbid, all three tentacles, then prepare to see your precious character get slaughtered in a manner of seconds if you don't get out in time. Unlike Torchoak Grove, this boss isn't bugged; it's actually meant to do this much damage.
** [[TrueFinalBoss Malachai]] can make Dominus seem like a walk in the park, at least when it comes to tactics. He rarely gives any breathing room in his attacks, constantly spawning projectiles and creating stuff on the floor that damages you if you stay there, forcing you to be one the move during the whole fight, and if you do find a safe spot then he'll just teleport to you and unleash a devastating shockwave if you don't move away. There's only one attack that gives you an opening and even then you need to mind all the damaging stuff he spawned beforehand.
** Izaro in the Endgame Labyrinth, especially in the final room. Izaro himself is tough, since he charges at you, fires shockwaves at you, or has a screen-sized ground slam, depending what weapon he's wielding that day, and the ground slam especially is a guaranteed one-shot kill against all but the most durable characters. He also has a phenomenal amount of health, taking most characters a long time to wear down. The Goddess is even deadlier, chiming in with her mortar bombardment, which is quite capable of instantly killing more fragile characters if they get caught in the middle of it, and will occasionally teleport anyone close to Izaro into a large number of traps. Further, unlike Izaro, she cannot be distracted or taunted and will never target minions or totems, always aiming for the player. And in the final room he may or may not have impossible-to-remove buffs from his two previous fights and the arena is covered in traps, decreasing the space you have to get out of the way. This is one of the most-complained about fights in the game for a reason.
** Innocence is a pretty good introduction to [[DifficultySpike what you're in for]] in regards to the bosses in ''The Fall of Oriath''. While High Templar Avarius was manageable, Innocence is basically the Shaper Lite, constantly filling the screen with [=AoE=] attacks, almost all of which can do ''over 900 damage'' even on characters with the most armor you can have at that point in the game, meaning that he can nearly-one shot even characters who heavily built their characters around life. You ''will'' be hearing the words "I am the ___" many, ''many'' times before you finally kill this bastard. What really makes Innocence stand is, aside from Doedre the Vile and Kitava (both mentioned below), none of the new Act midbosses and end bosses are ''nearly'' as hard as he is.
** Doedre the Vile is an unholy fusion of PuzzleBoss and DamageSpongeBoss. She has by far the biggest Energy Shield of any enemy you've encountered thus far, and due to the main gimmick of constantly switching the cauldron fluid she uses to attack, she will always become invincible for several seconds as she absorbs the fluid, meaning that the already massive energy shield is constantly regenerating. Said gimmick? The cauldron in the middle of the arena is constantly filling with either a red, green or purple fluid. The red fluid causes Doedre to spam her exploding blood orb attack, the green fluid causes her to spawn hard hitting zombies, and the purple fluid continuously spawns [=AoE=] clouds that rapidly drain your health. You think you can just leave the cauldron on one phase the whole fight so Doedre doesn't go invincible? ''Nope''. Every few seconds like the current fluid is active, you're slapped with a steadily increasing debuff that effectively doubles the damage you take from all sources, and the only way to remove it is to change the cauldron's fluid.
** The final battle against Kitava. Even the most hardcore players agree that this fight is absolutely ridiculous. While all of his attacks are telegraphed, he performs them so quickly that even those with max move speed will be struggling to avoid them. As the fight goes on, he will start constantly summoning minions who are just as capable of shredding your health as he is. Finally, when he's done to the final phase of the fight, he'll start spamming an incredibly powerful flame [=AoE=] that, due to both the incredibly small arena and how the attack blends into the arena itself, is very difficult to determine where it will hit. And the kicker? As of version 3.0.1, the fight suffers from a GameBreakingBug that will occasionally cause Kitava's defeat to ''fail to register''.
* ThatOneLevel:
** Back in the day, ''The Battlefront'' of Act 3 used to be this. The worst part of this zone was when you came across the mage variants of the Black Guards who constantly use a thorn-type of spell that causes any form of damage taken from the player to be copied back at said player. It was ''absolutely'' brutal to player builds not dumping their skill points into increasing their health or shield, which usually resulted in instant death. Overtime, the Blackguard mages received nerfs to the amount of damage returned to the player that it's hardly noticeable anymore.
** ''The Lord's Labyrinth''; a giant maze of traps and monsters that must be fully completed without dying...and having NO checkpoint system for the ability to do a portion of the labyrinth, then come back at a later time. Unless your character is built to rush through the dungeon to reach the Izaro fights, the length you have to go in order to get the Ascendancy class for your Exile is just disgusting. This was made easier in later patches, so that usually the hardest part is fighting Izaro himself instead of the corridors between each stage of his boss fight.
** Several high-tier maps have this reputation, but the most notable is the Hall of the Grandmasters, which is filled with the most powerful Rogue Exiles in the game. It's difficult to the point of being flat-out {{Unwinnable}} for most builds.
* ThatOneSidequest: Some of the missions for the Forsaken Masters can be very difficult or almost impossible depending on a characters skillset. For example, it is quite hard to solve Vorici's missions of only killing certain enemies, if your character heavily specializes in AreaOfEffect-skills. Haku's missions are considered to be especially hard for almost everyone, because they are very strict [[TimedMission Timed Missions]] of quickly reaching a certain place in narrow, monster-infested caves, in a game that often forces the player to proceed carefully. Oh, and it also throws indestructable Totems into the mix, that attack the player with elemental damage.
** Timed Quests from Zana can be downright unwinnable in some cases, because they might expect the player to find AND defeat a map boss in under two minutes without being able to extend the time. And that doesn't even takes into account the potential for getting some really unlucky map-modifiers.
* TheyWastedAPerfectlyGoodCharacter: For someone who's proclaimed himself as the new ruler of Wraeclast, it's actually quite surprising how little [[TheEmperor High Templar Dominus]] contributes to the plot. Given her recurring appearances throughout the first three story Acts, you'd think that the BigBad was going to be Piety. However, for one final Act 3 quest after the player deals with Piety, Dominus enters at the last second as [[FinalBoss the one]] [[TheManBehindTheMan behind her]]. ''Fall of Oriath'' somewhat rectifies this by making it clear right from the character creation screen that Dominus is the [[spoiler:initial]] BigBad, while also adding new NPC dialogue that fleshes out him and his plans.
* TierInducedScrappy:
** The Marauder got some flak as this. As the pure Strength class, he focuses on powerful melee attacks and armor that is purely defensive. The problem is that, towards the end of the game and ''especially'' the higher difficulties, you pretty much ''need'' some form of ranged attack and evasion/an energy shield to stay alive without having to guzzle potions every other second. However, come 3.0, he was massively buffed thanks to [[GameBreaker Vaal Pact]], making him extremely powerful in the endgame.
** Several [[{{Commons}} spell gems]] usually get this reaction due to higher level gems being perfect upgrades in comparison. A good example is the ''Fireball'' gem you acquire right at the start of the game, but then gets replaced by the infinitely better ''Firestorm'' gem that can be used a couple level-ups later.
*** Actually subverted, as many low-level spell gems can be extremely effective if combined with the right support gems, thanks to their low mana cost and versatility.
** Chaos Inoculation and Energy Shield. This pair has been, for several leagues, the hands-down best defensive option in the game with nearly every quality build making use of it. It is capable of getting more than ''triple'' the equivalent hit points of a Life build with similar levels of gear while also regenerating much faster and making a player immune to the nastiest damage type. This is widely hated by poorer players because the popularity and effectiveness has made good Energy Shield items incredibly expensive. It's also hated because of the fact that [[SerialEscalation as these builds gain more energy shield they require enemies who deal more damage to kill]], which leads to enemies dealing higher damage and players who aren't using this mechanic getting [[OneHitKill one-shotted]] with increasing frequency.
** In general, parts of the high-tier endgame map system are only viable with certain build- and equipment-choices (in Hardcore at least). Otherwise, expect to be killed almost instantly on a regular basis because you didn't have the foresight to have both massive energy shield / life and life leech to stay alive past one or two hits. It is especially annoying to have invested into a character only to find them useless, and it's more likely that most people will simply give up rather than start over entirely.
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