I mean I can't be, Right?

I recognize people how they walk in general. Put one of my friends in a crowd and I look for backs, not faces.

I don't have stairs, but I can recognize them by how they close certain doors.

I usually can tell just from the sound of their steps when in the house. Some quiet, some loud, some plod, some stomp and so forth.

The sound of their steps

Me too, and where they step to make stuff creak, and their breathing. My sister says she doesn't know when I'm coming because I walk quietly.

Yeah, same with pets

I recognize by how they walk

I often recognise them by their response when I call out “who’s that?”

I can tell as well.

I had a Three-Step System for knowing when my dad was gonna open my door because he never knocked. If I heard one of his loud footsteps, I was fine but on alert. After two, he's closer to the door but maybe he's going into the office room. If I hear the third step, I had exactly one and a half seconds to stop masturbating and look natural before the door opens because that third step is the point of no return.
It never exceeded three steps and he never came into my room after only two steps.

I can distinguish my individual family members by the sound of them walking around. It's weird

I recognize co-workers by the way they push their damn carts