I until recently thought I were just unable to visualize faces, but able to recognize them well but it seems my mind has only played tricks on me. That I just notice other clues, mostly the situation probably, and then my mind tricks me. You see before Christmas I signed up for a 1-day lab-course in biology to prepare for my exam (As I mentioned I improved some grades by reading on my own). There was this short blonde teacher (I looked him up on the web later so now I remember that much) who had the course. Two weeks later I met the same guy (it's often like that in small towns) and another neutral teacher for my exam in biology (Do not know what it's called in English, but it was an exam which included showing of some lab work and speaking about a random topic). Anyway a week after that again I met a new guy for the same pre-exam course in chemistry (this was a tall black-haired dude). The very same evening after the day I actually had that chemistry exam (it was postponed several times since he was sick). And just like in biology I knew that the guy I had the chemistry course with would be 1 of the 2 teacher who would evaluate me and ask me questions during the exam. As I were standing in the lobby of the school trying to figure out where I was going I saw two teachers walking in, talking to each other about some exam related stuff. There were no doubt in my mind that one of them were the dude I just met a few hours before, the chemistry teacher, so I nodded my head at him. I expected him to say hi and tell me to follow him or something, but he just smiled at me and kept walking. So I followed him through the building and into a room with other pupils. After a while I knew I were at the wrong place, because everyone around me were reading biology which seemed odd while waiting to be called into a chemistry exam. So I went sort of confused out in the hall and then I noticed the actual chemistry-teacher. Turns out there were still other people having their biology exams that day. So I guess all my brain figured when I first saw him walking into the school was "have I seen that man before - yes", and "does he fit the expected environment and behavior of the chemistry teacher I know will arrive here soon - yes". Because it turns out they could not have looked more different, and as mentioned I had seen the chemistry teacher for several hours the very same day! Freaked me out that I apparently are that bad at faces, and that it's still almost impossible to realize it yourself. Perception truly is way more than just the raw impression.