*thinks on anything sinful there is to be done* Hmmmm...
I... really... didn't? Like, anything? I don't steal stuff, I don't litter half the town with my casks, don't cheat on Seb, don't turn our children into birds, never once sided with Joja, never said a single bad thing to any of the townies... Heck, I don't even kill mobs in the mines, despite them definitely wanting to kill me. And those legendary fish I'm catching would definitely have a safer - and much more... fecund - life in my ponds than in open waters that have a fishing festivals going trice a year.
Man, I'm curious now. I'll be lurking this thread, maybe I'll see someone else's confession that would remind me of something sinful I've done.