If you’re walking down the block at nighttime, and two dipshits/parasites jump up, asking you very politely if you wouldn’t be interested in any hash..

If one steps up to your friend and the other tries to control your mind and vision by saying: “Regarde la lune/Check it, right the moon is right there!”,
while the other one tries to pull of the classic: “Let me show you a football/karate trick.” ..

Don’t be amazed, or at least try to look unamazed, and tell them:
“Guys, we don’t smoke, we know the moon is right there, we know that football/karate trick and hell, we live right there…”

If you’re lucky, that’s about all the urban knowledge you’ll need for the night.
In our case one guy ran away, while the other tried to start a conversation/discussion, which was ended before it got started with the classic line: “Bonne nuit!”.

Seriously though, keep in the back of your minds, in case you didn’t know already. This, of course, was an easy lesson to learn.