This happens to me so much in dating. Men will create an idea of me and from some point on just stop listening to what I'm actually saying because they "got me all figured out" already. It really amazes me how in the beginning they're always so enchanted and attentive until it's not a novelty anymore, then bam, whatever idea they created of you stays forever.
This happens to me a lot because of the way I look lol. I work in corporate and before nobody took me seriously even if I had the best idea, or what I said made sense, because I looked like a kid. I look younger than I actually am (got carded when I was 35).
I grew a beard (thank god I didn't get the asian curse of whispy fu manchu type shit) and a mustache, and it stopped.
Happens to me a lot when meeting girls or other people too. Just one look and they decide I'm the big party guy that drinks a lot and have a lot of girls on call. Really motherfuckers?