You can only use them when you really really need them.
Ah the sea cow, such a majestic creature!
Nothing says "I love unicorns" like a gigantic pendant with a picture of a unicorn and a rainbow. Hanging another one in the middle of your forehead also helps.
You know what my collarbone is missing? A moustache, that's what!
If you need glasses as bad as I do, you know how you can come to resent people who only wear them for fashion. Just give them a necklace. Posers.
I was never good at folding origami, this is much more convenient.