So many times I've pulled through a parking lot, looking for a space, only to see the usual idiocy:

SUVs parked in spaces marked "Compact". Better yet, some guy with a honker truck, jacked up to here with monster tires and huge -- well, I can only think of hooter envy--parked in one of those striped off triangular spots that are "no parking" because they are intended to remain empty to give you maneuvering room.

Then there are the folks who own cars costing 6 digits (I see a lot of them parked in handicapped-only spots, but that's another topic for another time), who park straddling the white line that divides one space from the next, so paranoid are they about getting dinged. Whenever I see one of these, I make it a point to try to squeeze into the space next to them so that they have to get into their vehicle on the passenger side and slide over. I usually "combat park" but I'll make an exception for these folks and drive into the space (so I can get out of my own car on the driver's side).

More than once, some rich bitch has come screaming out of the store when I've done that and I just lock up and walk away. If there are a few dings on my old car, they are just notches on the coup stick.

One space per car. And it's only courteous to park as nearly centered in the space as possible.