I read/skim/follow a bunch of rss feeds. It's a handy way to follow something without the overhead of joining a mailing list or the like. That said there's some feeds that do things that are downright annoying. Sometimes to the extent that I unsubscribe. If you run a RSS feed, try NOT to do these things:

• Feeds that are just links to posts. If I wanted that, I would have just visited your site. If there's no information or context, just a link you are wasting the features of rss and I (and many others) will likely just unsubscribe.
• Feeds that are cut off at a arbitrary limit. I understand that some sites prefer you read the posts/articles on their site with their style, etc, so they cut off the information in the feed to try and 'hook' you in to reading the rest on the site. Sadly, pretty much all of these I have seen have been set to some arbitrary limit, which often makes the 'hook' make no sense or provide not enough information to make me interested. Just include all the content. :)
• Constant edits. We all have been there where you need to go back and edit a post to make something important clear. However, if your feed constantly reedits posts it means that I will constantly re-see them. Don't cry wolf, but use edits very very rarely.
• Posts that are entirely a video or audio file. Sure you can point to or show a video or audio file, but if there's no text for context or reason why I would want to take time to watch or listen to it, I am not going to.
• Have the link for your post/entry not actually go to that post/entry. I have had feeds that redirect all links to the top level of the blog or redirect you to some stupid sign up page, but yet the feed has the content. This is very annoying if you are trying to go comment on something.