I regret spending years trying to make others (parents, siblings, others) around me happy & conform to their ideals / wishes, instead of trying to make myself happy.
I regret following their advice getting married to someone I already knew at the time I didn't fully want to get married to, then having kids because that's what everyone else felt was right for me. And I "regret" meeting other people who I know would make me happier, but not knowing how to get out of my present position, without making a ton of people (incl. little people) unhappy in the process...
(and hopefully I'm not going to regret not having posted this under a throwaway account)