I would've figured it out sooner, but I had a headache.

I recently purchased a store brand of flavored tortilla chips.  After the first few times I ate some, I thought I felt a little "off", but I wasn't sure.  Last night, I realized I had a headache.  "I wonder if the chips have MSG," I pondered.  Sure enough, it's on the ingredients list.  Scratch that snack food off my list.