Whats your lists of mistakes when doing DIY's?

[thermal]

-grinding without goggles
-doing electrical work without unplugging the battery
-using a 9/16 vice 14mm wrench/socket
-always snapping the rear lower control arm bolts
-spending all my money on I/H/E thinking it would make power... so I turboed later
-welding without gloves nor goggles
-welding while pants are soaked in oil... burnt the bottom of my pants
-using crescent wrench
-shorted out my O2 sensor cuz the wire was laying on the exhaust pipe, causing the insulation to melt and blew almost every fuse in my car

... theres more...