Does that count?
First let me begin by saying where I am on the SJW scale: I'm a straight white male of good health, on the tallish side, a couple of SDs out on the high side of IQ distribution, without obvious physical defects, raised in the suburbs in the midwest. My mother had a good income and my stepfather had an even better one. I've got pretty much no privilege cards to play. All yuor privilege are belong to me, is what I'm getting at.
So when it comes to microaggressions, I can really dish them out, I suppose. But I can't recall many.
One I do recall happened 5-10 years ago. My truck was having a problem and so I went to an auto parts store. At the counter, I asked the graying gentleman standing to diagnose my problem. He called over a curly-haired young woman and asked her opinion. She ID-ed the problem based on his relaying of my facts to her. Then I asked him what I should do about it, and again he turned to her, and she answered. After a couple of rounds of this, eventually I purchased the parts I needed and left.
It took a couple of weeks before I realized that I had treated that young lady pretty poorly. I should have caught on to the fact that she was the only one of us who understood the problem and just stopped interacting with the old man. If I were her and had been treated like that, I would have been pretty upset. "Ask me the questions - I'm the one with the answers". In my (slight) defense, the old man could have handed me off to her no problem with a simple "I can see that <name> knows what the problem is, I'll let you talk to her while I work on something else" and perhaps (my memory is not perfect) he tried something like that and I didn't catch on. Perhaps not.
So that's my story: A tiny sexist/ageist microaggression I committed because I didn't see clearly through my preconceptions. Of course the old guy behind the counter is going to know more about fixing engines than the young girl, right? And maybe he did - maybe he was training her, and if she had said something 'wrong' he would have corrected her. Maybe I would have done better if I hadn't been ticked off about and preoccupied by my truck problem. But really, I did her wrong by not recognizing her expertise.
Anybody have any similar stories?