What unusual graffiti or objects or whatever, have you seen while walking around, that made you smile?

here’s one I saw written on a sign outside University College London

I thought it was a nice change from people signing their name or other incomprehensible crap in spray paint all over the place.
So what sort of things have you seen that you didn’t expect to?
Something someone had written, or an object, or something someone had done to something that made you smile, or stop and think.
I’d like to know, I like these little quirks of humanity.

One time I picked up a newspaper on a train and on the inside page someone had written, ‘Don’t worry, I don’t mind you nicking my newspaper. There’s a great story on page 9’
Which amused me haha