A few years back, one skill I realized that I have is that I can recognize people at a distance. I recognize them by the way they walk, the way they dress, their height and a couple of other cues that I can't really explain. As long as I have met the person a few times, I can pick them out even when they are in a crowd and it takes only a second or so for me to realize that I know the person. I may not remember the person immediately or place him, but I will be sure that I know him. I've had a few false positives here and there but never a false negative. This is in complete constrast to noticing things around me. I could walk past a shop multiple times and not see it, not realize that a picture has been moved, not realize that my friend got a new phone etc. All these things come as suprise for me, but never with people. I don't consciously observe or study how people walk, dress etc but apparently my brain processes it all. I can't explain it, I just know.

I read about a year back that a person's gait can be used for biometric identification (something which I wondered about because its seems to be the primary way I recognize people). The article linked to a pdf that showed an attempt at designing a system that recognized people from their gait. It was incredibly difficult and complicated because you needed a lot of sensors to measure, bunch of high level math to process and prone to failure because the gait would change if you were carrying a heavy bag, walking on a slippery floor etc. Yet, the brain is capable of doing all this and adjust to situations all in a fraction of a second. It was the first time that I was seriously blown away by how incredible the brain is.