Personally I rarely look at anything in terms of success or failure. It turned out differently than you planned? That's interesting and something to give you a mental fillip while you deal with it. You got driving somewhere? New places to explore. You missed meeting up with someone as a result? Probably got a silly tale to tell them of how stupid you were to miss the signpost next time you meet.

I once got so lost going to an interview I ended up over a hundred miles away from where I should have been. Had a crazy story to tell for years afterwards.

I don't subscribe to this self help "every setback is a new challenge" attitude either: striving for 'success' the whole time is overrated.