'Seinfeld' ('The Non-Fat Yogurt,' 1993)
By this hit show's fifth season, NBC had ceded nearly total creative autonomy to Jerry, Larry David and their staff. So what better opportunity to explore the virtues of whether or not to "work blue"? Seinfeld himself had typically remained curse-free in his stand-up act; David, of course, not so much. Up to that point, they'd cracked heads on clever ways to color within the lines of network decency. (The series' famous fourth-season episode, "The Contest," went to great lengths to avoid using the word "masturbation.") But when a non-fat fro-yo outpost opens up, their confection is so "fucking good" that no other description can suffice. Then the shop owner's son, Matthew, overhears and parrots the phrase around town, forcing Jerry to assure the boy that "cursing is not something most comedians do." Until Matthew unspools his rehearsal tape, in which case it's both funny and appropriate to lash out at the "little piece of shit."