In the opening scene of Fallout 3, with the nuclear devastation, and that opening song involving not wanting to set the world on fire, and only wanting to start a fire in your lover's heart. Now compare that to John Henry Eden, who speaks of his country that he loves so much, even referring to it as his "dear, sweet America," and who says he wants to reach out into you, the listener's, heart. Now, remember that Eden is an amalgam of the personalities of dozens of Presidents, including the warmongering ones who triggered the nuclear war with China. And note Eden's long-term goals. They may not have wanted to set the world on fire, but....
You do the tutorials in Vault 101: a number associated with the most fundamental college courses.
The necessity for Project Purity is often questioned - however, there is no apparent farming infrastructure compared to the West Coast. The soil and ground water were either intentionally salted by low yield dirty bombs, or contaminated by the Vault 87 FEV. If you could de-contaminate an entire river, you'd restart the area's ecosystem.
Fire ants. You know they shoot fire because of the name. But that's not actually what it means—it means they're literally giant fire ants; the fact that they shoot fire has nothing to do with it.
Some people complained about the stereotypical 'little green men' aliens (Mothership Zeta DLC), and their equally stereotypical technology. But Fallout is set in a fifties stasis. And back in the fifties, that's what people thought aliens were like, so their design is keeping in perfectly with the setting.
The Pitt is quite possibly the single most uninhabitable place in the Fallout universe - And that's saying something. Why is this? In the 50s, Pittsburg was so polluted, and the smog so thick, it was not uncommon to have streetlights on during the day. It's since improved in the real world, but Fallout's US never advanced culturally past the 50s. The air and environment of the city continuously got worse until the day the bombs hit... It may have degenerated further with radiation, but Pittsburgh was almost entirely toxic to start with.
"Way Back Home:"
Similar to "Maybe" in Fallout 1, listen to "Way Back Home's" lyrics. Fitting to the Lone Wanderer's banishment from Vault 101, his former home, after either peacefully and violently fixing the chaos.
Alternatively, the song represents the Lone Wanderer's desire to return to their in game home -either the shack in Megaton or the suite at Tenoenny Tower. Both are places you can safely retreat to after the day's action, both can be customized to your tastes, both give you the chance to sleep well rested as well as the availability of commerce options nearby. In every way, those places are much more of a home to the Lone Wanderer than Vault 101 ever was.
President Eden's plan was to release FEV to exterminate the mutated inhabitants of the Wasteland, when President Richardson's plan in Fallout 2 was... to release FEV to exterminate the mutated inhabitants of the Wasteland. It seems like lazy writing. But Eden is a computer, who contains all the records of the presidents of the US, from Washington to Richardson. He would have known all about Richardson's plan, and being a computer, he's completely lacking in imagination. It's not lazy writing to have him aping Richardson's idea, it's positively brilliant. Especially if you stop and consider that the plan technically wasn't flawed and failed because of just one One-Man Army grandchild of a regional hero, something that shouldn't happen in D.C.
Littlehorn and Associates... who would be so evil as to hire people to kill others? The Enclave is paying Daniel Littleton to hire anyone merciless enough to hunt down others since life is cheap and microfusion cells are better spent on abominations than on pathetic sacks of meat.
Many people note the hypocrisy of an African-American like Eulogy Jones leading the Slaver faction - however, Jones' philosophy of Might Makes Right (with the slaves being slaves because of weakness, rather than racial inferiority) is reminiscent of African warlords who enslaved those who were captured during wars with other tribes - and since Jones and the Slavers sell off their slaves to other factions and individuals for the right price, this is also reminiscent of the warlords selling off their slaves to the Europeans during the colonial era.
At the end of Broken Steel, you have the option to fire a Kill Sat on the Brotherhood's base. Now, why didn't the Enclave did this before? Because it's the Pentagon, one of the symbols of the Old World and of America's power. It would be far too valuable as a symbol if they can re-take it. Of course they wouldn't fire on it.
Plus, this adds a reason as to why the Enclave would want to destroy the Brotherhood. Not only are they "impures", but they also dare to act as if America's symbols (the Pentagon and the Washington Monument) were theirs. Not to mention they use one of these symbols as a radio tower.
Why do the Raiders decorate their bases with fresh corpses on hooks? Well, there's no farmland around so, oh, well, that explains it. Of course, killing and eating other human beings isn't sustainable as a long-term solution for hunger but since when has that stopped psychopathic killers? It also explains why they attack first and always. They're hungry!
The Capital Wasteland seems to have more bandits than people. Where did they all come from and who are they, precisely, raiding. Well, there's numerous Vaults with particularly sadistic mind-control experiments going on. Likewise, just because there's very few settlements now doesn't mean that was always the case. It's quite possible the Raiders have destroyed most of the Capital Wasteland's inhabitants and are working on the last of them.
East Coast Super Mutants getting Stronger with Age neatly justifies Fawkes being such a Game-Breaker with Broken Steel: he's from one of the first few batches of Super Mutants (he remembers the Vault being shiny and new, after all), making him ~200 years old, much older than most of the muties you and he chew through. And he still has all his faculties.
The names of the weapons in Mothership Zeta are incredibly generic and dull- "alien atomizer", "alien disintegrator", "drone cannon", etc. Then you realize these aren't their actual names, they're just the names your character has given them in-universe to tell them apart. They probably have proper names, but there's no way you could ask the aliens to tell you.
The same could apply to Earth weapons you pick up elsewhere. Yes, those weapons have proper names and models. But your character's education came from Vault curricula. It's unlikely that you came out of Vault 101 educated in how to identify weapons. The names showing up on your Pip-Boy are based on information found etched on the weapons themselves, told to you by whomever gave you the weapons, or made up by you when you first picked them up.
Horace Pinkerton mentions he stole a memory module from Vault 112 to give the android a new identity and bury his old memories. In Vault 112, you meet one resident of the simulation who has become aware that it isn't real, while everyone else is ignorant. What if Pinkerton stole the module from her pod and that's why her real memories have resurfaced?
The Yao Guai are ordinarily sudden, silent face-ripping death, but if you have Animal Friend and thus the leisure to watch them 'at rest' it's pretty apparent that their mutation is extremely painful to them. No wonder they lash out at everything!
Why are the Outcasts listed as "evil"? Well to the rest of the Wasteland, they probably are seen as evil. After all, the Brotherhood they're used to are generally kind and altruistic (By Wasteland standards anyway) while the Outcasts are scornful to every wastelander they see, and the people at large probably fear them because of their attitude and potent technology.
Wernher not allowing you to bring your companions to the Pitt actually makes a lot of sense if you think about it. The Pitt is way more guarded and reinforced than Paradise Falls or the Lincoln Memorial are, so shooting your way in is out of the question. You will have to infiltrate as a "slave" and then wreak havoc from the inside. A ghoul, super mutant, dog or robot seemingly following a slave everywhere would have attracted too much unwanted attention, while Jericho and Clover would have blown the Lone Wanderer's cover in a different way. Jericho most likely gained a lot of infamy among raiders for surviving as long as he did and then "retiring" from the life, so the Pitt raiders would have recognized him miles away and wondered why he is suddenly following this slave around. Clover is Eulogy's bodyguard, and since the Pitt gets most of its slaves from him, Ashur would have recognized her a long way off, probably conferred with Eulogy and the cover would have been compromised. Star Paladin Cross most likely would have also been recognized by Ashur as being Owyn Lyons' bodyguard, causing him to wonder what she is up to here.
When using the Chinese Assault Rifle, one will notice that the weapon degrades faster then the regular Assault Rifle. One common trait noted of the AK is how reliable and durable the weapon is. So why does the Chinese Assault Rifle degrade faster? It actually reflects Soviet/Communist supply doctrine. You see, to the Communist forces, weapons are used until they breakdown. Afterwards, they are replaced. This is opposite of Western Doctrine, in that weapons are repaired when they break down. The two types of assault rifles represent this. The Chinese Assault Rifle is expected to be replaced once broken, while the regular Assault Rifle is expected to last.
At the end of Broken Steel, the purifier is already providing clean water to the wasteland. Go to the river near Jefferson Memorial and one will notice the mirelurks are near death. Why? Because the purifier cleans EVERYTHING, not just radiation, so the water becomes fresh for humans to drink. Mirelurks are based on horseshoe crabs, marine animals that need seawater to live. The freshwater is killing them in the process.
Some people didn't like that the Lone Wanderer can not side with the Enclave. But why would he/she? They were responsible for James' death.
Some of the Vault-Tec bobbleheads can be found in places which reflect the stat/skill they enhance:
Endurance is in the Deathclaw Sanctuary, a place full of tough creatures (you probably need more hitpoints when venturing inside).
Intelligence is inside Rivet City's Science Lab.
Barter is in a store (the cave under Evergreen Mill).
Big Guns is found in Fort Constantine. Not only the item is inside a military base, you actually find it next to an ICBM's launch codes (i.e. a very big gun).
Energy Weapons is in Raven Rock, inside Colonel Autumn's bedroom (the Enclave uses only this kind of weapon).
The general area containing the Lockpick bobblehead (Bethesda Ruins) doesn't matter much, but the bobblehead itself is located next to a locked safe.
Medicine is in Vault 101, either on James' desk or in the clinic, depending on when you pick it up (in either case, in a place related to medical care).
Melee Weapons is in the Virulent Underchambers of Dunwich Building. Melee weapons are quite appropriate given the presence of ghouls, and also the classic Dungeons and Dragons RPG vibe.
Science is in Vault 106 (most vaults, including this one, have been built to perform experiments on their inhabitants).
Small Guns is in the National Guard Depot's Armory (the weapon storage facility of a military base).
Sneak is in Yao Guai Tunnels, a place inhabited by sneaky animals.
Speech is in Paradise Fall, inside Eulogy's Pad (Eulogy Jones has 10 in Charisma).
Unarmed is next to Argyle's corpse (in the Show Within a ShowThe Adventures of Herbert "Daring" Dashwood, Argyle is a master in kung-fu).
In The Adventures of Herbert "Daring" Dashwood radio show, the ghoul Argyle is described as a master in kung-fu. You actually can find Argyle's corpse ingame, and according to his stats, his Unarmed skill is decent yet average (59, which is slightly lower than his Small Guns score; both are his tagged skills). It's not necessarily Gameplay and Story Segregation, since the real Herbert Dashwood states this radio show isn't entirely accurate and portrays Argyle as an Hyper-Competent Sidekick who regularly has to save him, which was Character Exaggeration.
You can stumble across a wrecked, abandoned farmstead. Read through the logs and get some warm fuzzy feelings about how people are still thriving in the post-apocalyptic world. Reading the last log, you figure they got spooked by some raiders and decided to up and leave. But on the way to the farmstead, you pass through an area called the Grisly Diner, a raider-occupied, trapped diner, complete with seemingly freshly-cut bits of bodies hanging from chains. Oh, Crap!.
Mama Dolce's is revealed to be a front for a Chinese covert-ops cell back before the War...and the long-ghoulified Chinese are still there, refusing to abandon their post after 200 years. Given what's found in the files and terminals there, it's implied that none of them can leave, due to them believing that the Great War continues to rage long after China itself was obliterated with America. And that, even after spending centuries trapped in "enemy territory," they're still waiting for orders to come home that will never come.
Exploring Vault 112 and Tranquility Lane raises a number of very disturbing implications regarding the inhabitants - specifically, their age: all of the residents in the Tranquility Loungers appear to be adults, despite the fact that in Tranquility Lane, one of them is a child. Then, it's revealed that Braun can control the appearance of his captives within the simulation, and Dithers actually states that little Timmy Neusbaum is "not really a boy". So... just how many times in the last couple of centuries has Braun transformed people for the sake of his games? Does anyone in the Vault retain their original appearance? Was Dithers elderly when she entered the vault, or did Braun transform her into an old woman for his own sick amusement?
On a related note, the memory chips in the tranquility loungers allow Braun to control the memories of his captives and their personalities - judging by the fact that James doesn't seem to behave any differently than a real dog while in the simulation. So... once again, just how much of the residents' behavior is genuine and how much is just due to Braun's meddling? Are the Rockwells really having marital difficulties, or is that more brainwashing? Was Timmy really that emotional in the real world, or was his personality altered? And most disturbingly of all, what else has Braun been using his power over memories to do to his captives? The implications do not look pleasant.