Spent 3 hours trying to fix a clipper that just needed the blade re-seated

Last Tuesday I had a Wahl Senior that kept pulling hair on the left side of the blade. I figured it was dull so I swapped in a brand new blade, still pulled. Took the whole thing apart, cleaned out 6 months of hair dust from the motor, oiled everything, put it back together, still pulled. I was about to tell the guy the clipper was toast and he needed a new one when my shop mate picked it up, looked at the blade for 2 seconds, and said the cutting blade was seated crooked. He popped it off, snapped it back on straight, and it cut through a test patch like butter. Three hours of my life gone because I never checked the most basic thing first. Now I keep a little flathead on my station just to check blade alignment before I touch anything else. Any of you got a dumb fix story that wasted half your day?