When replacing the starter on Mom's car in the parking lot at the mental hospital where she works...
...keep a close eye on the tools. Better yet, put the toolbox back in the trunk and only pull out the tools you need.
Also, less rain gets in the toolbox when the sky (of course) begins to piss down rain and lightning the moment you wiggle underneath, and a delusional guy with bushy hair appears out of nowhere to watch and tell you he's building a flying saucer for Jesus. And you notice him staring hungrily at the screwdrivers and chisels...
Scratch that -- I think if I could go back in time, I'd actually just tell myself to first look inside the car, slap my forehead, and put the shifter in park.
1983 Suzuki GS850G, Cosmic Blue
2002 Suzuki Vstrom DL1000, Midnight Blue
2005 Kawasaki KLR685 - Turd II.2, The ReReTurdening
"Do not crinkle your food wrappers loudly. Be considerate to others, or I will bite your torso and give you a disease."