Bad call, bad pass, bad ending...
Cruise through the sports page on any day, you'll find the reporters who rethink what could have, and perhaps should have happened. And if reporters aren't doing it for you, then you can always check in with a coach, or a player, locked up in a film room, rehashing the missed opportunity that led to the defeat.
How many times have you hashed through a missed opportunity? A play that didn't turn out the way you had intended?
You watch film on it. You study it in stills. You keep salting the wound.
What are you second-triple-quadruple guessing right now?
Drop it. The game is over. Time to move forward.