Signal Ahead

Every area of the country has some unwritten rules of driving. I'm told that in Boston, when a light first turns green, people turning left will make their turn even though they have no green arrow. In Florida, if you want to get somewhere fast, you need to surf the ever-present ambulances. In Seattle, cars actually yield to pedestrians.
Around here there are still some rules I don't quite get. At a 4-way stop, the first to stop is the first to go only if the first to stop is not making a left across the way of the second to stop. In this case, the first to stop is supposed to wave the second to stop through or vice-versa. The first to wave is the second to go. I don't know what happens in a wave tie. I refuse to wave because I actually know the rules for a 4-way stop.
On my way home, if I go a certain way, I'm traveling west on a street that has an intersecting north-bound street. For people traveling east, there is only a small turn lane and that can sometimes cause traffic to back up a little going east. Quite often I'll get behind someone (or several cars behind them) traveling west who will stop at the intersection and start waving cars through. I suppose these people think they are being polite and doing a good deed but, in fact, they are not.

1. They are nearly causing an accident by stopping on a through street for no (good) reason.
2. They are being rude to the people heading west who then stack up behind them.
3. They are causing a logjam of westbound traffic that eliminates the westbound traffic gaps that normally occur so that the next eastbound left turner (the one who missed Mr. or Mrs. Politeness) is stuck for quite a while.

Let me know of any unwritten traffic rules where you live.