Magikarp, Bidoof, Metapod, Rattata, Goldeen, Jigglypuff, Zigzagoon, Cascoon/Silcoon, Luvdisc, Pachirisu, male Combees, Glameow/Purugly, Purrloin/Liepard, Vanillite (Just because it's ice cream), Litwick (Just because it's a candle), Stunfisk
Of course, there's Zubat, Machop, Onix and Geodude, but it's only because they're in EVERY game.
Personally, the only Pokemon I really hate is Hypno because it's so creepy o.o
Bad Pokemon have problems too, they're just like you, except their Pokemon.
The world needs to open their eyes, and realize, they're not perfect and sometimes they die.
For me it's Smoochum - the baby evolution of Jynx. It is just so disgusting that it wants to kiss us despite the fact that it is a baby. And it evolves into Ganguro trainwreck Jynx, one of the ugliest Pokemon ever.
I'd have to say Garbordor. Despite the fact that he's no worse than Muk and Weezing, so many people, nostalgia-blinded and otherwise, seem to hate it for any and all reasons. I'd even go so far as to say that people generally hate it more than they hate Zubat, which is a pretty impressive feat.