Not using your phone while doing your business

It’s “unseemly” for anyone to take the phone into the bathroom, private or public, says Diane Gottsman, an etiquette expert. In a private bathroom situation, the person on the phone doesn’t want to hear you doing your business. In a public bathroom situation, the person on the phone doesn’t want to hear you and everyone else doing their business, and no one in the bathroom wants to overhear your conversation.
Not minding your boundaries in public

It’s also unseemly to invade the personal space of others in a public bathroom, Gottsman points out, and personal space boundaries are more sensitive in public bathrooms than in other venues. So, when choosing a stall or a urinal, as it were, if you’re not erring on putting the maximum possible distance between you and anyone else who is already there, you’re breaking bathroom protocol.
Not dawdling in public bathrooms

This applies regardless of whether the bathroom is single- or multi-stalled. In a single-stall bathroom, your hanging around is potentially keeping other people waiting in line outside the bathroom. In a multi-stall situation, your idling is potentially keeping “bathroom-shy” folks from doing their business.