I Like Onions but Onions Don't Like Me

My grandmother use to say that every time we went out to eat Chinese food. Every time. I would look at her and wonder what the heck she was talking about. If you like onions, eat onions. Well, at 12 nothing really disagrees with you, so it's hard to understand stomach problems. Now that I'm older, I like onions, but onions don't like me. 

I imagine there's a world of things I could have learned from my grandmother if only I could understand her better.