Showerthought: a guy in Tucson paid me $40 to fix a 'broken' derailleur that just had the chain routed wrong
That was 2 weeks ago and I'm still laughing about it because I spent more time looking for a real problem than I did on the actual fix. Makes me wonder how many shops out there are selling full drivetrain swaps for stuff that takes 2 minutes with a hex key. What's the dumbest 'repair' you've billed someone for that turned out to be nothing?