If they're actually "playing" a "routine", then that's totally a problem. If they're pretending to be someone they're not in order to sway people's opinions of themselves or be manipulative, then of course that's not a good thing, but their true motives do have a way of coming through with time. Asking God for discernment about someone or something is always a great idea, IMO.
But people who are legitimately nice, kind, and polite? I don't see that as a negative thing at all. Sometimes nice people are looked upon with suspicion simply because true kindness is rare these days. People tend to wonder if their kindness is just an act. But I don't think a little suspicion is a bad thing, because sometimes kindness IS just an act.
Just don't go overboard with cynicism, give people the benefit of the doubt and an opportunity to prove who they really are.
I'm not completely sure that my response was on topic with the OP. Lol