I hear a from a lot of guys that thy don't get enough compliments and that effects their self-esteem, so I do try to hand out compliments to the men I know. But I also don't want to be the creepy older woman that makes someone feel uncomfortable (and I am genuinely not hitting on them) so I try to be careful about how I do it. I wish more people would take into account how a comment is going to be received instead of just throwing it out there.
And butt pinching is right out! The worst!
There's a huge difference if someone says "You look nice today!" , "That new haircut looks great.", "You look like you've lost weight." Etc. Those are totally fine.
It's when people start saying "Oh your forearms are so muscular." Or "aren't you just the hottest thing I've seen all day." That it gets weird.
Compliments are fine, sexual objectification is weird.