The only thing I can't think of that has made me rage quit would be working on cars. It frustrates me because it doesn't take long to realize that all car manufacturers find humor in making things incredibly difficult for the average joe...everything needs a special tool or you can't reach a part without removing every other part around it..Or worse...both.
dude. HVAC is the same sometimes. The worst is freaking Lennox man... everyone uses normal parts except for them...