I'm going to nominate McDonald's and their wet floors.
Yes, legally they had put a wet floor sign in the entrance to the toilets......
I lead my 3 year old to the toilet door, open with my left hand, kid walks through and goes down like a sack of shit with an almighty bangzi slide toward him in an effort to get him to his feet, arms waving frantically to try and stay upright. Genuinely less available friction than an ice rink. I understand there was a wet floor sigh but this has to be the slippuest surface I have ever had the misfortune to shuffle across.
It wasn't a case or read the sign and walk with caution, anything but gentle vertical pressure resulted in an immediate meeting with the floor.
I'll then nominate my son for insisting in 3 wees, only one of which resulted in the expulsion of wee twat.