Spaces that are small enough I might get stuck. Not small spaces, just ones where I might go in and not be able to get out. I could have never been a tunnel rat in Vietnam.

Also IVs and having my blood drawn. I had a couple rough experiences with getting IVs when I broke my arm when I was little, ever since then I have issues. I get lightheaded and dizzy if I have to get an IV or have blood drawn. This is a bit of a conundrum since I work in a medical setting.