Charlie Brown regrets the time his KITE got eaten!
I regret that I broke every heart I encountered
this means, "Fuck! I almost had it and then it all went to hell GOD DAMN IT I WAS SO CLOSE!"
to succeed but still feel like you could have done better (used exclusiely in the expression: くい が のこる)
the most general, broad, useful word for regret
I regret getting my HEART broke, but I despise all PEOPLE.