But you're ok with the guy's first response to the confrontation was to shove a grown man hard enough to send him flying?
There's not a single correct decision made in this entire scenario, from parking in the spot illegally, to yelling at the woman, to shoving the man, to shooting the man. There is absolutely no defense for any of those actions, and applying different thought processes provides evidence that each action is the primary reason the man is dead. I know the chain convenience stores I visit in Atlanta (QTs, Racetracs, etc.) have a security guard outside, maybe to prevent incidents like this.
Bazza, I think the "Hill of beans" comment was in regards to the man's reaction to the infraction. You go tell the store manager or an LEO, you don't go psycho in the parking lot attempting to shame them.