I've been taking care of them the right way since I joined AC. Before that I was keeping 5 female bettas in a 1g bowl, :barf:, for a few months.
Also way back when I was 4, and there was a pretty big LFS in town, I had a pleco, 3 guppies, 2 cardinals, 1 albino cory, 1 kuhli loach, 1 normal cray, a fiddler crab & a red clawed crab in a 10g :crazy:. This can be counted in the stupid mistakes section, although I was only 4 and it was a "I want that one!" situation. It's sad, considering my mother was making the purchases, and she was (and still is) a very good vet. Just didn't know about things with fins.