For me I think it would be vanilla. I've always liked the smell of vanilla but its taste as it is would be so bad, haha. If you add it on a food though in fairness it makes it really taste good, but taking vanilla extract as it is doesn't seem to taste better. I could say the same for garlic when you use it on food. I like the smell but I don't like the taste. What about you? Can you think of something that smells really good but doesn't taste as it is?