First - Repairs after a big racetrack crash where the bike slid and then cartwheeled after crashing around 70mph in a corner. Bike would have been totaled for sure if it was a street crash. It took me months to fix everything considering I was working full time.
Second - Repairing a coolant leak in a horrible spot that required removal of gas tank, airbox, EFI system, etc.. massive surgery. The leak was not that bad but was driving me insane and the shops were all trying to talk me out of doing it as they said they'd charge me a lot.
Those big motorcycle maintenance jobs were insanely rewarding once complete though. And I think they cause you to really view that motorcycle as "yours".
Some bike jobs I do find tedious (cleaning) but things like adjusting a derailleur I'm so good at it I can do it in my sleep so it's quick and hard to get bothered.
Bicycle stuff that bothers me is stuff like routing internal cables or bleeding badly designed brake systems. I do tend to do those though as the shop will charge like $100/hr labor for it and tell you that you have to wait weeks for them to do it. Bicycle tools are super overpriced but they still pay for themselves after only 1-2 jobs!
Bicycle repair does not grant as much of a rewarding feeling when your done and so much bicycle stuff is throwaway. The components all wear out pretty fast and are mostly not repairable.
