I am, to be fair.
But I get over it quickly.
For instance (this is a true story), I was approached by a young man and what I assumed was his girlfriend just the other day. I had observed the couple before the approach, having noticed - in particular - that the young man was not wearing visible socks. Naturally, I decided there and then that he was a scoundrel.
(This adventure took place at, or very near, a bus stop in a moderately large city).
The young man asked me whether I knew if a certain bus (one that was scheduled to halt at this very bus stop) was going to X (this being a location in the centre of the city), to which I replied in the positive. The young man was not only polite but also decidedly pleasant on the whole (I could mention other details, but I especially noticed his smile - which was genuinely friendly and not in any way ingratiating), and I realized there and then that I had been very wrong to condemn him on account of his socks (or rather lack thereof, or more accurately the lack of any visible proof that he was wearing any).
And - yeah - that day I learned a valuable lesson.
(I still think he looked like an absolute twat for not wearing socks, but I also think there is a chance - at least - that he was a half decent human being).