Yeah i guess messing up was certainly what could be levelled at what happened in our last two FA Cup semi-finals, especially the Man Utd one where we took the lead and were in control before Dembele's c0ck-up.
The other times we've gone out generally the situation has been:
a) the other team have had a better team/squad to play us or
b) we've used some of our more 'squad-level' players in key positions and not been able to quite play at the level we would in the league.
Some of those that fall into b have been disgraceful though, such as the games vs Leicester in Poch's first season (FA Cup), Palace (FA Cup) and West ham (LC) last season.
Edit - I guess, when you go out the less 'what if' thoughts re what team was played the easier to 'get over' the disappointment...i think...