My experience is that this one-off is generally used as a way to be a dick to people who live a life you don't agree with, or that is opposed to your own.
I have yet to meet a boring person. Everyone is a hot weirdo when you really get to know them.
It's a matter of overcoming your own ego and realizing that your 'boring' is just another way of living.
Subsequently, those sort of bullshit phrases always serve to piss me off really, really badly. Who are you to tell someone else that they're boring? They're just living their lives. Why not take a minute to get to know them? If they try to drag you down and make you something you're not, then yes, avoid them. But just to make a snap values judgment on whether their life has value? No.