Tired of crazies

So I drive an old Grand Cherokee that I bought for 500 dollars. One of my back tires is so bad off, it must be aired up at least as often as I gas up. Sometimes I go out to find it low or nearly flat, and then bee-line to the closest (about a mile to mile and a half away) gas station to air it.
So the other day, I go out, and unbelieveably both my back tires had gone nearly flat overnight. I stared at them both blankly and then frowned, but they had not even the decency to look embarrassed about it.

I got in and began my trek to the gas station. At a light, a man in a truck next to me begins to wave and yell. I know what he's going to say, but don't wish to seem rude. I roll down my window.

"Lady, do you know you have two flat tires?" He says as in a tone as if to say I caused this by having a uterus.
I nod, showing my tired frustration, then begin rolling back up the window while saying, "thanks!" cheerily.

"Lady!"
"Yes?" I stop the window.
"You have TWO flat tires!"

I consider explaining the difference between flat and nearly flat, as well as pointing to the gas station I'm in the lane for, but instead just nod, with an expression of 'sorry' on my face--as if I'm truly sorry for making him have to tell me this while we are stopped at the light.
"Well," he begins with pure exasperation, "you need to get them fixed!"
By this time I'm fed up with Captain obvious and mumble "Yes, Dad."
He doesn't hear me, but he can see I've said something, and so replies--I'm still trying to believe he's still talking to me and depserately want the light to change-- "You have to do something about that."
Finally, I've had it and ask, "You wanna give me your spare? I'm just carrying the one, and BOTH my tires are flat!"

I mean seriously you'd think he'd notice I'm OBVIOUSLY having a not so great morning as it is. The light changes and before he takes off he yells,
"Witch!" Only he mistakenly used a B instead of a W.

It actually takes me a moment to take off and turn into the station I'm so stunned at this reply. I'm amazed that my bad morning had so personally disgusted and offended this man in his gigantric truck.

I told a friend who explained to me that to vehicles, apparently flat tires are synonymous with flipping the middle finger, and so I had just given him a double birdie.

So now I guess I get it. I am just not that fluent in car cussing I guess.