I'm not face-blind, but I do have difficulties recognising people.
When I worked in a shop, I sometimes had to leave a customer while I fetched/checked/did something. Then, when I came back, they had sometimes moved to look at something while waiting and I often didn't know who I had been serving (which was a bit embarassing). If I remembered to do so, I would take a quick look at their clothes, shopping bags, hair etc., but sometimes I would forget to do that or forget the details or someone wearing/carrying something similar would go and stand nearby.
Sometimes I had to sort of stand there looking confused as if I couldn't see anyone and wait for them to tell me that they were there. Sometimes I had an idea who it was, but couldn't be sure, so I had to be careful to avoid eye contact with them, otherwise it would look strange if I was staring at them but not doing anything about it.
Once in secondary school, I was really surprised when I found out that one of the lunchtime supervisors were actually two different people! They were around the same age, did the same job, had similar hair styles had similar(ish) voices etc. and I hadn't seen them together before. I was shocked! However, seeing them together, I could see that they were actually quite different.
Anyone else?
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I don't have Aspergers, I'm just socially inept
Dodgy circuitry! Diagnosed: Tourette syndrome. Suspected: auditory processing disorder, synaesthesia. Also: social and organisation problems. Heteroromantic asexual (though still exploring)