Bad Public Toilet Etiquette: Building an intricate layer of four layers of toilet paper so there is absolutely no chance of any of your ass making contact with any of the toilet seat.
When you're done, make no effort to flush or otherwise dispose of your barrier, so the next person to use that stall can appreciate your construction skills.
haha they'll just have to build on top of your already admirable work
A few more uses, and the paper stack is larger than the toilet itself, and then you have to borrow a stepladder from the custodian. That's a whole other level of awkward.