These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
For North Americans, the fact that after three years (likely due to copyright issues regarding the real life products in the game) the Wii revision of Pikmin 2 is finally going to be released in June 2012 for only $20!
Broken Base: You're much more likely to find someone who specifically enjoyed one of the installments than someone who enjoyed both of them, with the sequel generally attracting more fans. They're very different games and they're both very good, but the idea of a linear game on a timer is too much for exploratory players. On the other hand, the second game treats the Pikmin as much more expendable and the original foreign atmosphere is somewhat lost.
Demonic Spiders: Spotty Bulbears, especially in the second one. They're hard enough to kill in the first game without losing a sizable chunk of your force, but in the second game they come back to life if you don't harvest their remains quickly enough.
Food Porn: Did anyone else feel hungry reading Louie's notes on cooking the various wildlife?
Try doing Gluttons Kitchen for the first time and not crave desserts afterward.
Game Breaker: Yellow Pikmin's Bomb Rocks in the first game, Purple Pikmin themselves in the second. Both despite having negative traits, no less.
Unless you're going for a No Casualties Run. Bomb Rocks are a double-edged blade and can blow up your Pikmin as well. Purples are increadibly slow even with flowers sprouted, making it harder to get them out of the way of unexpected trouble.
Good Bad Bugs: In Pikmin 2, if you find a drop of spray (red or purple), it is possible to get 2 doses out of one drop by getting both your captains close to the droplet, and pushing the inactive captain with the active captain. The inactive captain will start to collect it, and if you get the active captain to start collecting it as well, you will get 2 doses of spray instead of one.
Hell Is That Noise: *WEEEESHHHH* *CRASH* *WEEEESHHHH* *CRASH* *OOOOOOWARRRRRRRRR!!!* followed by the sounds of ineligible mumbling and the sounds of Pikmin being helplessly squished.
Most Wonderful Sound: The sound of a Waterwraith being destroyed after dealing with it for five levels straight.
Tastes Like Diabetes: According to one of the item's description, Olimar created a musical for the Pikmin.
Tear Jerker: The song Ai No Uta, which, in the first person, describes the Pikmin's feelings on becoming Olimar's willing slaves helpers.
The other song Namida Ga Afureta is equally as heart-breaking, because it shows that Olimar DOES love the Pikmin in return, but has no way of using simple words to tell the Pikmin.
On a no-Pikmin-death run, the Segmented Crawbster probably takes the cake.
To say nothing of the Man-At-Legs. He can kill a WHOLE GROUP of 100 Pikmin if you're careless enough!
Waterwraith on levels 1-4 of the Submerged Castle. He's easy enough prepared, but when you don't expect it and are not prepared, you can be devastated quickly, because it's merciless.
That One Level: The Submerged Castle, with the Waterwraith dropping in if you linger on a floor for too long. There's also the fact that you can only take Blue Pikmin in when the dungeon has all hazards. Including the one that instantly kills Pikmin. Luckily, you get Bulbmin to alleviate the problem.
The later dungeons can also fit, the Wistful Wild ones in particular.
Ugly Cute: Some of the enemies like the Bulborbs and Toady Bloysters tend to be this.
Woobie, Destroyer of Worlds: The freaking MAN-AT-LEGS, believe it or not! Yep, that creepy mechanical spider that blasts your Pikmin to oblivion with a gun. How? According to its journal entry, the Man-at-Legs has no need for the gun since it has no natural enemies, leading to the rumor that the gun controls the creature! Let's look at it from the Man-at-Legs' point of view... imagine if you had a gun attached to you that killed everything around you that moved, and you were targeted by a giant swarm of insects for reasons beyond your control.