Strangely we wonder why people do it at inappropriate times and in awkward places: during family dinners, at a party, during a trip to the mall or supermarket, etc. Poor timing and placement can be embarrassing and messy. You have to do it in the right place - outside is okay, in private is better. Of course, in order to do it in the right place, you might have to hold it for a little while, until you can get out of the room or across the hall. You might also have to wait for someone to finish so that you can properly express yourself.
But even when people learn where to have a fight (or pee) people don't always know that they have to be precise. Don't make a mess. Right? So wipe the seat or even better: aim. What I really mean is, tailor your message to your audience. You wouldn't sit on a urinal would you? So why would you talk to a man the same way you would to a woman?
Women in particular are often told never to do it at all. Then we wonder why people explode at inappropriate or inopportune moments. Cultural mores dictate that women aren't supposed to entertain bodily functions or show anger. Freud may have been more right than I had previously thought... except about women. If you're telling a woman that she isn't supposed to pee... er, get angry; that it's irrational or unmerited, don't blame her when she can't hold it any longer. She needs a special place and designated time to vent, just like a man does.
Human waste is never pleasant but if handled properly can be relatively painless to remediate. Be thoughtful in when, where, and how you approach your shit so that it doesn't hit the fan.
Good luck with your metaphorical toilet training!