If I resorted to booing during/after every bad performance over the last 45 seasons of watching Athletic I would be permanently hoarse.
In my time I have seen more downs than ups, more poor performances than good ones. You have to savour the good ones and try to forget the bad ones (not easy I admit)
Where I sit in the upper Main Stand there is constant slagging off of players if a pass goes astray or if a chance goes begging. If the players were perfect they would be playing at the highest level. The younger players (who seem to get the most stick) will improve with encouragement from other players, staff & fans. Constant stick will only de-motivate players. Yes, I know they are professionals and get well paid for playing
Anyway rant over
Conclusion
If you have enjoyed the performance, applaud, if not just leave quietly at the end.