I have a mental association with bad handwriting and smart people. When I was little I always assumed that any doctor or engineer I met would have bad handwriting. It makes me wonder a bit if I subconsciously glorified bad handwriting, perhaps thinking that if I had bad handwriting myself, I'd be smart.
My handwriting isn't all that bad. I get a lot of people telling me they really like it, and my share of people telling me that they hate it. (The text in the header of my blog is in my handwriting, if you're just joining us.)