There's a story around here about a woman in a Cadallac Escalade who was searching for on-street parking for over an hour. (I know, if you buy a Caddy, pay for parking, but I digress.) She finally found a spot where someone was getting ready to leave. Ignored all the honking as she waited patiently for the spot to empty, then pulled forward to back into the space in standard parallel-parking fashion.
At that point a little Fiat zipped into the space.
She got out screaming at the guy who owned the Fiat for stealing her spot. He just grinned and said, "Well, that's what you can do when you're small and fast."
In a huff she got into her car, slammed it into reverse, and proceeded to torn the Fiat into scrap metal. Now it was the Fiat owner's turn to start screaming. She just smiled and said, "That's what you can do when you're big and rich.
All that to say, you're big. Go ahead and back into your slot - even if it's already occupied.
Nobody on this earth is bad enough for me to wreck my car over. Especially since, if it was wrecked, I wouldn’t be able to buy another one.
So I just sit at the laptop and wait for them to start their car up, then I grab my keys and by the time they are ready to put the gear in Drive, I’m in my truck and backing into my spot. So what, if I have to wait for a day? Irritating, but not maddening.