[seiji]

Missed regret serves to say, "Next time, I shouldn't be so timid. See? Nothing bad happened."

Acted regret serves to say, "Why did I do that? I should have known better. I'll remember not to do this again."

Minimizing missed regret is just quieting your ego and moving forward so opportunities don't pass you by. Minimizing acted regret requires seeing all possible futures and avoiding ones with high probabilities of failure (but that's quite boring).