I think my blog technology is “comment friendly” although I do have one of the pet peeves in place: comment moderation. My reason for commenting is purely selfish but that’s all a part of blogging.
I guess my pet peeve would be the captchas. Sometimes those things are very difficult to read and, quite honestly, they’re annoying. But I think most people have these things in place because they aren’t sure how to disable them or they haven’t taken the time to learn about the different settings on their blogs.