The ad shows people in everyday life, with the addition of extra body parts.
-A wedding takes place. We see close-ups of the bride/groom's hands, and we can see five fingers and a thumb.
-A receptionist is filing her nails whilst simultaneously using her extra arm to hold the phone to her ear.
-At a bar, a man with three eyes notices a woman with three breasts.
-A clothes store is seen with clothing to accomodate the extra limbs.
-A jogger is seen with three legs.
-A person with two heads enters a hairdresser.
-A florist give a flower to a two-nosed customer.
(You can suggest extra ideas in your comments)
A voiceover states that some people like a little extra something. Meanwhile, a woman goes to her fridge and gets the product in question. She has a taste of the product, no flavouring, and isn't impressed. She then adds the flavouring and has another taste. She likes it. As soon as she has had a taste of the flavoured product, she grows an extra arm. This impresses her even more.