I thought about fixing that, but it seemed like a yak shave…

Good gravy, I did nothing last week but shave yaks!

"What are you up to?"
"Yak shaving"
nods gravely in pained agreement

What the hell are these people taking about? Let's clear it up.

A Yak Shave (or Yak Shaving) is the end of a chain of incremental causal dependencies. Imagine the situation where you need to do a, but first you need to move b out of the way, and then you can’t move b because of c being broken, so you go to fix c, but that needs tool d, and tool d is only sold at store e, and store e is run by a person you promised to do f for, and before you know it you’re busy doing x, y and z, where z is breaking into the local zoo, and y is shaving a yak, because x needs yak hair to complete.