If you had red sauce on a pasta, or pizza, or any Italian or Asian food for that matter, then you had garlic. Garlic that's in your face - like roasted garlic - is something I can imagine people not having until they're older, but it's what garlic does behind the scenes that would be missed in ways I can't imagine (and wouldn't want to imagine).
Now, as for oysters...did the game change to "what would you happily give up"?
I like properly prepared oysters on occasion, but they're very far down the list of "can't live without" foods.