Oshawott (It's kinda cute, I guess, but it's pretty obvious why people are calling it "derpderp".)
Dewott (Hey, it looks cooler now, I guess this Pokémon isn't hopeless after all. Can't wait to see the next evolution.)
Samurott (What the hell is that thing?!!?)
It's even worse for the Snivy family, sadly Snivy is the coolest looking Pokémon in its family. Goes downhill from there.
And while we're on Pokémon that experience a downgrade in awesome-lookingness post-evolution, while Gengar looks pretty cool, I maintain that Haunter looks way cooler than Gengar.