When you think someone is completely trustworthy and a nice person to whom you can tell all your secrets, but then they betray your trust and stab you in the back multiple times.
You: Hey that Brett Brookstone looks like a pretty nice guy!
Me: Whoa there buddy, he's brookstoned some other people before.
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.