Do you have any unwearable fragnances?

I’ve seen a lot of comments for some fragrances that they are unwearable. Personally i dont have fragrance like that in my collection (megamare is close to that because it’s very very strong).
But what makes fragrance “unwearable” is it how strog it is? Or is it the type of smell that is just disgusting? And if that’s the case why would anyone have a fragrance like that in their collection.