Luckily haven't witnessed any real bad ones, but have been at a few where I helped direct traffic until duty units arrived, etc. Once up in the mountains, light rain, we had been going up to go shooting and since the weather tanked we were still going just to have a day in the mountains. For those familiar with the area, the intersection where AngelesForest Highway turns off from Angeles Crest Highway. Some guy went right through the stop and got rear t-boned by a Forest Service Attack Pumper. It spun off and hung up over the side against a tree with the rear wheels in the air. It ain't gonna go anywhere for a while. And the guy spun into one of the sign posts in the intersection, with the rear quarter destroyed along with the wheel, tire and axle knocked off. He aint going anywhere either. Thanks to seat belts and reasonable speeds, nobody hurt too bad. We helped lay flares and a few bandages. And stuck around for CHP to get there for statements. Got a half box of flares from the CHP to replace the half dozen we put out.
Was on the 91 in rush hour once when either a tow truck or flatbed of some kind lost about a half dozen 8 ft long 4x4s and they started bouncing around like toothpicks on uppers, bouncing all over and off of things, few fender benders and rear enders, then as one is coming at me, I ducked and it hit across my windshield long way on and cracked it good, then I sat back up still slowing and the idiot in front of me had stopped and the 18 wheeler is frantically blowing his horn. Luckily the guy in front floored it and I just missed being the meat in the sandwich. Seemed like half the drivers reacted by paing attention and the other half just panicked and drove any which way.
On the 210 in moderate heavy traffic, we saw a car spin out for no apparent reason and slam into the center divider and then accelerate back all the away across to the right side and hit that barrier. Nobody hit him, but there were a lot of artful dodgers on that one.