My parents were never trustworthy either. My motto is "Hope for the best, expect the worst." My DH is completely reliable, as are most of our friends, but I still never commit to doing anything unless I know I can pull it off completely on my own. Probably why having children never appealed to me - single parenting looks really hard. But even something small, like a couple friends asking if I want to go to a movie - I don't say yes unless I am prepared to go to that showing of that movie alone. I take commitment way too seriously.