Nor do I. There are only so many symbolic amusing possibilities that you can convey through a small image and Clippy is already taken.

I like the simplicity of the current interface.

I most emphatically do not want clippy-haters on this site, such as User:orthonormal.

I think that the lack of avatars helps me treat a person's argument independently from that person, reducing any tendency toward ad hominen responses. I suspect that this is true for others on the site as well.

They help with recognition of people and social aspects, but it's not clear that either of those things are things we want here.

There could be configuration options for those that share your sentiments - but I think thumbnail images should be on by default - especially when viewing user pages.

Well, for those of us who think more visually than textually, they do help with recognition of individuals.

I'd support the inclusion of avatars in users' profiles, and possibly attached to comments in explicitly social subreddits/forums/etc that may be formed in the future, but I don't want to see them on the main site, mostly because I don't want the layout to be changed to accommodate that level of clutter.

ETA: Also, having avatars on the main site seems likely to contribute to priming issues.

They add a personal touch. They help create the impression that you are interacting with a human being. They help with visually scanning for particular authors. This all seems like basic UI stuff to me.