Given that the exact same question is the current top post but for driving instead of transit, I feel this question was needed.
My answer: I saw some guys hooking up a Raclette Grill to the outlet in an otherwise empty German intercity rail waggon. They had it unpacked in one of these 4 person seats with a small table. No idea if that could work or if draws too much power from the board net. I just headed on to the next waggon.
People just pissing on the floor in NYC/Boston subways. Not really that unusual.
Not public transport, but a street parade on London. I saw a woman squat down, pull her thong to the side under her skirt, shit on the street, let go of the thong and continue walking all in about five seconds.
Never seen someone piss in a tram/subway in Stuttgart and we have an annual beer festival (the Stuttgarter Wasen) Here.