I've been playing video games for quite some time, but I think I only started to get attached to characters during my second playthrough of Mass Effect. Before that I was able to be a complete bastard to everybody and not feel bad, but I actually talked to my party members on my second playthrough and started to care about them, and I guess that jumped over to other games, because now I sometimes feel bad when playing as an evil character and have trouble making mean dialogue choices with central characters.