"Okay lost boy." (or girl)
Completely gets into their ooda loop. Very few will ask what it means, most just puzzle over it. You get into their heads. And if they do ask, you just say, "you don't see it? It's so obvious." And then just walk.
OR, and I've had fantastic success with this one lately, is to say something like, "whatever, you creepy-ass Trump voter." Gets in their ooda loop as well. Because if they're not a trump voter they'll deduce that what you said makes you not a trump voter, so kind of supposed to be on the same side. It's absolute dog whistling. They'll say no Boomer, and you say whatever, Trump voter.