[HKH2]

And instead of just shrugging it off, you could tag strangers that annoy you and end up with a giant list of grudges against a whole host of people. The false positives (e.g. twins and doppelgangers) should make it interesting.

[dylan604]

Take it to the next step towards Black Mirror where the AR shadows out people you've blocked and then mutes their voice so you can't hear them

[earthnail]

That would make for fantastic comedic situations when you then physically bump into them after you erased them from your AR vision xD.

[EwanG]

Which feeds into Saint Motel's song "You're Nobody Til Somebody Wants You Dead" which has a bit about how the list just grows and grows until it's everyone you've ever known...