Is you?

That isn't really the same thing. I am not saying you should flirt while in a relationship, I just think you are using a bad analogy

Here's a better analogy
Bitch, if you're already watching a great movie why the fuck would you then go to another movie that you don't know what the fuck its a bout and just watch the previews?!?!
How's that?

most of the flirting that people did is subconscious. Most of the time people will not know they are doing and it takes a few times for someone to pick up on it.