Ah, it can be terribly embarrassing, or not. A lot of people go to the bathroom - it's actually about the most universal thing we do and it's no big deal really.
A coworker told me she forgot to lock the door and the male boss opened it while she was on the toilet. It was a rest room with just one toilet, no stall to shield her from view. She said, "That was interesting." I think that's a good attitude.
someone walked on me while having a poo at a resteraunt and jyst laughed because i thought it was funny and then so did he. he probably forgot about it straight away.
Not at all. You should expect your staff to know your routines and habits. For example, after your morning coffee brought to you by your secretary, when you leave your office with the newspaper folded neatly, it means you are headed for the can to take a crap. They should know which stall you prefer and to keep it ready.