"Short order groove" joke

This guy enters a restaurant, and orders a milkshake, "Not too thick, not too thin, but in the groove man, in the groove."

The cook, who hates to be told how to cook, hears this and gets pissed off, but sends him the milkshake.

The guy then orders a box of fries, "Not too crisp, not too soft, but in the groove man, in the groove."

The cook is getting really pissed off at this, but he rolls up his sleeves and gets him the box of fries.

Then the guy orders a hamburger, "Not too big, not too small, but in the groove man, in the groove."

On hearing this, the cook storms out and charges up to the guy, and says, "You can just kiss my ass, not too much to the left, not too much to the right, but in the groove man, in the grooove."