andi,

I can understand your frustration. I think you are making more of the situation that it really was. This was not a case of discrimination. It was a case of the customer's confusion with the inconsistent information they received. It will be helpful if you can have some rehearsed responses for situations like this.

For example, You could reply, "Yes, you can come in any time you want but if you don't want to get stuck waiting, it will be better to make an appointment."

As Jo*Mar said, Mentioning your TBI may be counter productive. " I'm sorry. At first glance it looked like the day was booked solid. When I looked a second time, I found 2 openings."

The important thing is to rehearse these responses. The concussed brain does not respond well under stress. Having rehearsed responses ready will make it much easier to handle these situations. I used to spend hours calling back job leads to schedule jobs. I had to learn to memorize my responses or I tended to get flustered when the customer would try to make special requests. It was even more important when the customer was getting testy.

Maybe you can write down some responses on note cards to review from time to time. In my case, my wife could tell I was talking with a testy customer when she would here some of my canned responses. When dealing with customers all day, having a repertoire of canned responses can greatly improve your own tolerance for testy customers.

It can be a tough situation. I hope this helps.

My best to you.