*People who disconnect instead of forfeiting (I mean, if it's internet problems and not intentionally DCing, that's one thing, but I've experienced intentional DCs before and they suck).
*People who have six Pokémon in their party/Battle Box but bring fewer than six into battle (unless it's Battle Spot, of course- I'm talking challenging passersby on the PSS).
*Character customization being exclusively for Kalos, as opposed to a staple of the series. I want that fedora permanently!
*The complete lack of a cowboy hat for the player character.
*The lack of availability of Apricorn Poké Balls in games that don't include Johto. Can't any of those stores have Apricorn Balls imported or something?
*The inability to transfer items up between generations. It just feels like my Master Ball stockpile goes to waste whenever a new generation comes along.
*Yanmega can't learn Fly, a direct contradiction of its HG/SS Pokédex entry.
*Gyarados being part Flying. I mean, I get it- they didn't want to make it part Dragon because back then it wouldn't have had any weaknesses... but part Flying? And with no Flying moves to its name to this day outside of Bounce (which every fish can learn- hell, even Magikarp gets Bounce!).
*The fact that they finally had a chance to make Gyarados a Dragon-type with Mega Evolutions... and they make it part Dark instead. And wait even longer to give it access to Crunch (though I've had moderate success with a bulky, relatively slow Mega Gyarados that runs Payback).
*Weezing still having higher Attack than Special Attack, despite its impressive special movepool and its horrible physical movepool. Which brings me to...
*Weezing hasn't had any physical STAB since before the physical/special split. They even designed the perfect move for Weezing- Gunk Shot- and have consistently failed to add it to Weezing's movepool.
*Weezing and Gengar were able to get Sludge Wave from the Dream World (and Gengar also from a later event) but are incompatible with the TM. Just let them learn it naturally already!
*That blue pentagon that's barring some of my Pokémon from certain WiFi competitions. And some of them I can't just re-breed, because, among other things...
*Qwilfish can only learn Swords Dance from the move tutor in Generation III. The TM will not work on it. What's the deal with that?
*Similarly, Shedinja no longer gains any moves Ninjask learns immediately following evolution. Granted, Endure+Weakness Policy makes for a surprisingly adequate substitute for Swords Dance, but still...
*Shinies that are almost, if not completely, indistinguishable from their normal forms, like Seel, Garchomp, Persian, and Gengar.
*The jingle that plays when you catch a Pokémon. Generation I's was better than what it currently is.
*Nintendo's continued refusal to so much as acknowledge Missingno., despite its ever-growing fanbase.
*People on the PSS who set their message to indicate that they want a battle... and then decline your challenge.
*Hypnosis's accuracy being buffed to 70% at the start of Generation IV... only to be lowered back to 60% halfway through. Acid raid, a debilitating, game-breaking glitch, was allowed to persist until the end of the generation, but oh, no, this couldn't wait!
*Given the above, the fact that the Sky Drop glitch wasn't fixed for B2/W2, so instead they just kept Sky Drop banned. It's like a Contrary Spinda used Skill Swap on GameFreak's priorities or something.
*In-store events switching from wireless distribution to serial codes. I can't be the only one who likes to be able to download the event Pokémon without getting out of the car.
*All the Shiny-locked stuff in X and Y. Xerneas and Yveltal, OK, I kinda get that. Korrina's Lucario, sure, I understand that. Zygarde, the Kanto legendaries, and Snorlax, on the other hand, not so much.
*We can no longer tell if any of the starters are Shiny on the starter selection screen. HG/SS introduced what could have potentially been a big thing, only for it to be taken away.
*The Spiky-Eared Pichu's inability to be transferred to Generation V. I liked that thing! Moreover, the complete inability to deposit the Cosplay Pikachu in Bank tells me that a similar fate awaits it.
*Stuff that's good as-is, like Garchomp and Salamence, getting Mega Evolutions while the likes of Farfetch'd and Luvdisc are left in the dust.
*Low Sweep getting "buffed" to 65 base power, when the only reason anyone ever used it ever was on stuff with Technician.
*Kadabra's unique immunity to the Everstone- if it's traded while holding an Everstone, it still evolves, while anyone who makes the trade for that Haunter in Snowpoint City knows that that's not right. They call it a glitch on Bulbapedia, but if you ask me, this has Uri Geller's stink all over it.
*No way to change a Pokémon's Ability from its Hidden Ability to one of its normal ones. I know this is usually not an issue, but if I ever get a chance to change my Shiny Noivern's Ability from Telepathy to Infiltrator, believe you me, I'm taking it.
*No Battle Frontier in OR/AS. All the hinting should have at least led somewhere!
*The PWT not becoming a staple of the series.
*Voltorb and Electrode not being findable at the Poké Ball factory. Considering their origins and positions in the Kalos Dex, I fail to see how they passed up this kind of opportunity.
*People who misspell Qwilfish's name by replacing the W with a U.
*People who misspell Klinklang's name by throwing an extra G into the middle of it.
*The Berry Juice Shoppe in Lumiose City not being a thing in OR/AS. I had enough Enigma and Roseli Berries in Y to be set on Ultra Rare Sodas for a long time.
*Pokémon that only become Dragon-types by Mega Evolving not being allowed to learn Draco Meteor.
*Noibat's movepool. You would think a Dragon-type would get something in the way of a Dragon move without the need for breeding or a move tutor. You would think. Not even Dragon Breath or Twister!
*Anger Point no longer activating from behind a Substitute. Had a Primeape whose entire strategy was centered on that...
*Kalos going into full-blown drought mode as soon as your Sliggoo hits level 49.
*Heatmor's Speed stat. And inability to learn Flame Charge when every other Fire-type (not counting Heat Rotom) can learn it!
*Samurott's movepool, Speed stat, and relatively useless Hidden Ability (especially when compared to the gems Serperior and Emboar got!).
*FR/LG's soundtrack. It just... it doesn't feel the same way as Generation I's music, if that makes any sense.