Totally. I choose my avatar based on my mood. I don't know if people interact differently with me, but I assume they do, since I interact differently with them. Why? An avatar for me is a mix between a costume (which makes me get into character) and a ritual, like cleansing or shedding my old skin. It helps me move forward and let go of any expectations I have for myself that build up over time, in terms of the person I should be and the things I should say, and free myself. It's pretty deep, I guess. I should note that I don't actually think about all this when changing my avatar, but now that you've asked, that's how I'd interpret the process.
Regarding other people's avatars, yeah, I probably create some type of association with the person posting, and interpret it at some level. Some are funny, some think they're funny, some seem introspective and artistic, some seem unique, other just bubble-gum pop. Sometimes I'm conscious or the inferences I make, sometimes not.
The sexy avatars are a whole different ballgame. The associations I make are strong and automatic.
In the past I had a lot of cartoon character avatars because they made me happy (and Captain Haddock was actually one of my favorites! 
) and my dog for a while before that- complete with reindeer antlers. I may have the dog with antlers again once Thanksgiving is past and it's the Christmas Season officially again! (it's all for you, Jen!)
no.
