Internet telephone service provider Vonage has a commercial where a smiling couple, looking like they are the perfect example of two drones, show up on the doorstep of a new couple to the neighborhood, offering a pie along with a basketball-sized pile of wires as the "bundled" cable, phone and internet service, and even admit the disadvantages: incomprehensible bills and unexplainable charges. The new couple explain they have Vonage phone service. The welcoming female's entire persona - clearly an Unstable Stepford Smiler - "cracks" as she tries to explain that "everyone" in the neighborhood bundles. Her husband (more calmly) echoes her, also saying (with a lot of emphasis) that everyone there bundles.
That creepy Bob fellow in those commercials for Enzyte's "natural male enhancement". If you can't quite seem to figure out just what he's smiling about from the Double Entendre laden narration, give it time.
That is not a smile. That is a rictus of agony from unceasing pain. (He's probably suffering from continuous priapism, an unceasing erection that if not immediately treated can become permanent or cause the man to be unable to ever get an erection. This is that disease that erectile dysfunction pills warn you to see a doctor immediately if you have an erection lasting longer than 4 hours.) The eyes implore the viewer for the merciful release of sweet death.
The Burger King from the Burger King advertisements is a particularly disturbing example (it could be that he's wearing an actual mask though...).
How about the guy in the Axe commercials? He turns into chocolate and all the girls in town go crazy and take bites out of him, and all the while he sports that insanely creepy perpetual grin and wide eyes.