My mother was the type of person who thought a good souvenir was something which was trying hard to be clever, but actually was just really stupid. I'm not talking about things like an Eiffel Tower key chain, not that my very poor family ever went anywhere near France or anything. I'm talking more like a maternity T-shirt which says "Bahama Mama" in an attempt to make a lame wordplay on the idea of the drink and pregnancy. Yes, those are two great experiences that go great together, aren't they?
I think of things like wasabi caramels as the sort of thing people buy as a "bad souvenir" from Japan. I'm certain that they are not meant to be anything, but an interesting treat for Japanese people, but most Western folks are very preoccupied with anything that smacks as "weirdness" when it comes to Japanese food. Sugar? Wasabi? Sneak some to your coworkers when you get back from your foray into the land of the rising sun and watch the hilarity ensue! Guffaws, snorts of laughter, and a swift punch in the face for being such a supreme asshat could be yours for the price of some chewy globs mixed with wasabi powder.