On Parking Lots and Idiots

Why is it that as soon as people drive into a parking lot, they forget all about the rules of the road????

I almost got into an accident this weekend because some fracking idiot decided that he was going to play chicken with me in the grocery store parking lot.
Let me just say this: whether or not you have an actual, physical stop sign, you're supposed to stop when you reach the end of an aisle before crossing the "road" (or designated thoroughfare, or whatever you want to call the "main drags" in parking lots). Now, if someone is coming at you down that "main drag", you don't GO!
This is what happened.
Imagine a "T" shape. The left part of the T is the access to the parking lot from the main street. No stop sign. The top and bottom of the T are the "main drags" of the parking lot. Both have stop signs. The right of the T is the actual parking lot, the aisle where cars drive between rows of parking.
So I'm stopped at the bottom of the T. Fine. No cars coming from any direction. Fine. I go to turn into the left part of the T to get out of the parking lot. All of a sudden this idiot comes screaming up the aisle (the right part of the T), doesn't stop at the end of the aisle and tries to cut in front of me, honking all the time.
Now, I don't know what the rules are in the rest of the world, but up here, that counts as an intersection. And at the end of an aisle in a parking lot, there's an "unspoken" stop sign. Plus, I was already established in the intersection, so whether or not there was an actual stop sign, he was supposed to stop!!!
Grrrrrrrrr.

That's why I don't, as a rule, go grocery shopping on the weekends, let alone on Saturdays.

(Thanks for letting me rant.)