I think the worst was when I was at Fort Zancudo on the highway trying to jack a ride so I could get into the base and jack a Lazer.
I went to go shoot a driver but I accidentally selected my Grenade Launcher instead of Assault Shottie. So I nuked the car and I flew backwards and started a chain reaction. As I was floored I got hit by some cars who panicked and drove off. I was able to get back up and some other cars ran me over. I lost a bunch of health cause I got hit about 2-3 times. Then the car I nuked was on fire and it got rammed by a military truck from behind and pushed right into me. So as I finally got up the car hit me flames and all and I caught on fire and died. Yup the fire finished me off.
The only death I ever had by fire. Epic death. I was pretty PO'ed at the time but thinking back now it's hilarious.