Definition: In this task, you are given a Reddit post as a text. Your task is to generate a title for this text. The title should start with "TIFU by", followed by a situation that caused humor. The title should contain 7-12 words, ideally.
Input: Text: this happened yesterday. 

i was on a crowded bus in london trying to put my backpack on as it was my stop. i have had the same backpack for about six years so it is too small for me, i therefore have to do this weird shoulder role thing to put my pack pack on which involves throwing my arms forward. fool that i am, i made a sweet connection with the back of an old woman's head, and she went down like a sack of bricks.

everyone gasped and looked at me in horror, then some tracksuited man who looked like he'd done more drugs than charlie sheen hit me and made my nose bleed. as i fled from the bus people cheered the tracksuited man. 

when i got home i ordered a new backpack, it still hasn't arrived.

TIFU by punching an old woman on a bus.