Except they spit. It's how they express themselves. For 10 feet around any iguana roost, you'll see little off-white blobs everywhere. And if that happens to be in the front window of your groovy San Francisco apartment, where the iguana sits in the window all day and spits at passers-by... it gets pretty damn disgusting. (Not that I have traumatic personal experiences with a friend who had iguanas. In San Francisco. No problem at all. Blech.)
Dated a girl with a red tail boa and a savannah monitor. They were both mean, but okay, the lizard thing is kinda cool. Looked into getting an iguana. Looked in the mirror. Asked myself "self, what the fuck do you think you're doing? There are houseplants that are more interactive." And never got an iguana. I'm sure that would have been a real letdown.