Yes, really big window clean jobs, where you suddenly feel that price you put in is awfully low, or you won't get to those tricky to reach windows you promised were no problem, or they hate the results! All silly things that once you've done the done were not a problem at all.
PW is still a learning curve, so again when moving into high access stuff, roof cleaning I get a nagging pain. ( IBS brought on by a total barsteward of a senior manager who made my life hell for 3 years )
Darran