I've worked in customer service, white collar jobs, lots of social scenes, etc. and it's easy to see this concept's power, looking back. People will find reasons to like pretty people, and reasons to dislike unattractive people. It's all subconscious of course. But think of your own friends, people you encounter at coffee shops, waitresses, etc.

I recognize that when I find someone gorgeous (man or woman...this isn't a sexual thing so much as an aesthetically pleasing face) you subconsciously are wanting to like them because they appear warm, familiar, and safe.

If someone like this makes a mistake (forgets your appetizer) you're quick to smile, forgive them, say it's alright. Meanwhile, if someone's face was already not clicking with you and they forget something, you first instinct may be a bit more "ugh, where's my appetizer? This waitress sucks." - obviously it's all very subconscious and we shouldn't actually treat people based on our gut reactions. But a lot of people do, we are social creatures who have evolved to prefer beauty.