What is one of the worst/embarresing/ annoying/stupid things you've ever done

okay well i'll give an example lol. On フェイスブック someone from my school made a group where あなた 投稿されました stuff about the school like your memories. It was pretty good and i ended up posting something about my principal saying how she turns a three 分 assembly into a twenty 分 assembly. (purely meant joke wise, so please don't slam on me saying i'm disrespuctful) anyway my japanese teacher :) then told me the 次 日 that my principal has been monitering that site as well as police. Soo thanks jap teacher for the heads up hahaha.
Ps. I deleted my membbership lol. Hopefullyt nothing comes from it