Behavior I don’t get

If there’s one behavior I don’t get, it’s to try to intimidate others.
If someone doesn’t make eye contact or smile, I try to remind myself they may be shy… Because that’s how I was.
But.. People who intentionally try to intimidate you, ignore you (or look you up and down) & make you feel inferior… why?? That lacks class & in such an obvious way.
It makes them feel better about themselves? I don’t get it..