I can't name any pacifically but here is a stream list:
-TR episodes that have nothing to do with anything but being staying themselves.
-Fights with the main girl episodes.
-Pikachu-we-already-know-it-won't-evolve and Pikachu "will always be my best friend" episodes.
-Flashbacks that take up 50% of the episodes.
-Lab episodes. This includes seeing starters even before Ash gets them all.
-And pokemon bonding episodes. I understand they are necessary but I rather not waist my time.
Episodes I can't stand are the ones where the BW rivals are included but they either do nothing useful or there is one of them missing. Also any episode Trip loses and leaves.
About 90% of DP
That one episode in Hoenn with May BS defeating Ash and the whole town scolding Ash. Ugh, I'm not sure if I would be able to watch that crap again.
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Let's see... What episodes come to mind that drive me to insanity?
Well, most of Johto comes to mind, though I can't remember any specific episodes (you couldn't PAY me to re-watch Johto and Kanto again). But pretty much all of Johto as several Kanto episodes were unbearable (especially nowadays).
In AG... it seemed the most together and fairly well-laid out at times. However, "In the Knicker of Time" and "Zig Zag Zangoose" were lousy and pointless, especially with the shorts-obsessed kid. "Love at First Fight" was very tough to endure, "Maxxed Out" seemed pointless, "Judgement Day" was boring, but that's about all that come to mind in AG.
Moving on to DP... Anything with Piplup as center stage was tough to deal with. He REALLY got annoying after a while, plus his "development" was short and sparse. Anything with Hunter J also rubbed me the wrong way as well, since she was so intolerably evil and cruel (glad she met her doom). "Bibarel Knaws Best", "Luxray Vision", "Nosing 'Round the Mountain", "Sleight of Sand", the summer school arc, and anything with Kenny was unbearable and pointless. That's about all that comes to mind right now.
BW... good god... what a nightmare!!! Iris alone was too much to take, and anything, ANYTHING, where she was center stage made me want to hurl. I stopped watching the whole BW series mainly because of her and her "You're such a kid!" lines. Talk about irony at its best. On top of that, her catching a DRAGONITE was the final straw. But pretty much the whole BW series was a waste of my time. I hold no regrets not watching BW at all. A total disaster at best, though "Here Comes the Trubbish Squad", "Club Battle Finale: A Hero's Outcome!", "Scraggy and the Demanding Gothita!", and the Junior Cup arc are probably some of the bigger highlights (with the slight exception of Krookodile beating Dragonite and Iris crying like the little kid she is). But, above all, any episode with Iris as the star was simply, utterly, and completely the pits.
That about covers it. Better stop now before I really go off (not that I sorta haven't, but I could still rant off some more, but better stop while I can).
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I apply Felix's Law: "Smile, tomorrow could be worse."
Hunter J should have done more IMO. Like actually steal a cotd's pokemon in front of ashs face and getting away with it while ash leaves her ship headfirst in a straightjacket.
I also get bored and can't stand anything with max in it. People may think piplup is bad but max is way way worse.
fhat any episode that boring and pointless. Also all the episodes focused on Misty.
Many filler episodes, mainly in Johto and Sinnoh. Actually, Orange Islands had the two most boring episodes ever - the one with the Raichu zapping his trainer and the one with the Magikarp researcher. Ewww. Also, there was one episode in Sinnoh where a guy with a Snorlax tried to prove that the best way to train Pokemon is through science. Ash tried to prove him wrong and they both took part in a Poke-athlon. That Snorlax guy beat Ash no problem, but he STILL admitted to being wrong and praised Ash. That is like... so stupid!
I can't stand episodes where Ash doesn't use his on hand Pokemon or when they have lunch scenes and there are purposely Pokemon missing.
I've been making my way through the older episodes and there's this one episode in AG that is absolutely gag-worthy: Love at First Flight. Pokemon does a fair number of episodes where two Pokemon are attracted to each other, but tossing in their trainers in this sappy, sugary, "i'm too shy to admit i like her!!" set-up was so terrible that I had to shut the episode off and skip to the next one.
Any Best Wishes episode. After watching a couple, I can't bring myself to do it again.