^
I think mental attitude may be a factor, but probably not the determining factor. I've become so upset that I've started experiencing what feels like an allergic reaction, but this is pretty rare. Also, being relaxed can probably help things. Ultimately, though, I believe this is mostly about the physical. My problem for a while was trying to get relatives to understand that I was allergic to their dogs and it didn't really matter how cute the dogs might be. That wasn't the issue.