Here's a pet peeve:
ignoring a hand shake.
I don't get it. Because if I stick out my hand and introduce myself and ask what your name is, I expect you to stick out your hand and shake mine as you say your name. That's just what common courtesy evolved into in a lot of countries.
And when you refuse to shake my hand and stand at a distance instead, I begin to think critically about the kind of person you are and how you view me as an individual.
You are racist.
You are age discriminatory.
You are misogynist.
You are too affluent for me.
You are too good for me.
Clients shake my hands; the working poor, sometimes homeless, sometimes mentally unstable encounters shake my hands. And when you, some pretentious, old, conservative, Christian white couple refuses to shake my hands, I'm going to assume you're all of the above, and in turn, I now have no respect for you, a stranger.