Welcome to the first edition of What they didn't teach you in French class
There are two classes of French speakers. You either add quoi all the time or you don't. Now we aren't talking about the functional quoi here, the one that means "what", for example in "t'as fait quoi hier soir?" (what did you do last night)
This quoi is devoid of real meaning and is added to the end of any ole sentence for flavor. There is no equivalent in English - the closest translation I can think of is ", right?" but even that doesn't encompass the full spectrum of quoi-ness. I know this because on the last episode of Lost (which in desperation I bought off of itunes), they decided to do a little featurette on Danielle and the French scientists with subtitles. Bitch went crazy. Apparently she's also been wearing the same sweater for 20 years while everyone else on the Island gets shipments from JC Pennys. Well maybe not Sawyer. Wardrobe goes to PlaidsRUS in a little place called Williamsburg for his git ups. Hot shit models for Davidoff, no way he was going to accept the JCs
When one of the dudes said something (probably about the fucking smoke monster..mentioning the smoke monster, where has home slice been lately? I miss his human pulverizing ways) that went like "....sentence in french, quoi", everything was translated except for that one little dinger at the end. Furthermore Lost is right about everything, so I consider this indisputable evidence that quoi is meaningless.
Don't get me wrong though, quoi maybe meaningless but it's intensely satisfying.