[Closed] Most hazardous surface other than ice? Stories please.

I have three offerings:

Another for anywhere near astonhill or wendover, green slime on chalk or wet leaves on chalk. Your going down.

Crossing at Fenny Stratford over canal. Engineering bricks in the wet just when you turn right after crossing the swing bridge. Hurt bad and cost me a XO rear mech.

Mini roundabout up the road from me. On exit of a garage, diesel spill in the wet, turned right, first thing to hit the Tarmac was the side of my helmet, learned the value of helmets that day.

Things like this always remind me if taking my test 20yrs ago. The instructor asked us what you do when you hit ice on a motorbike. The answer. fall off.

That steep slabbed descent between Scammonden and Rishworth in the Winter. Wheels slipping all over the place over those wet slabs. Don't know how your supposed to ride this in Winter.