Harassment

A term sometimes used is "Energy Vampire". Someone, who just by the way they watch or behave, detracts from the 'positive energy' of the atmosphere.

The thing not to do is look at people like they are a zoo exhibit. At a zoo you can laugh at the monkeys. You can talk loudly about computers. You can say the baboon is ugly. Because you don't care what the baboon thinks about you. If the baboon looks at you, you don't need to acknowledge its attention. It isn't important.

Treating people like that is wrong. Don't do it.