ummm Kotor2: the plot, the fact that no matter how much perception your char has he can't pick out the fact that this woman who is teaching you is evil, and G0t0 for being a evil selfdestructive droid.
Kotor1: Carths I can't trust myself Lifestyle, Bastilas attitude in the beginning, and the ides that armor worn by Dark Jedi (Bandon) cannot support force powers.