Camphor

Ted: No, it's not an adventure, it's a mistake!

Lily: OK, yes it's a mistake. I know it's a mistake, but there are certain things in life where you know it's a mistake but you don't really know it's a mistake because the only way to really know it's a mistake is to make the mistake and look back and say 'yep, that was a mistake.' So really, the bigger mistake would be to not make the mistake, because then you'd go your whole life not knowing if something is a mistake or not. And dammit, I've made no mistakes! I've done all of this; my life, my relationship, my career, mistake-free. Does any of this make sense to you?

Ted: I dunno, you said mistake a lot.

- HIMYM