I'm interested in seeing which tag is responsible for marking a question as 'interesting'. A slight change to its visual representation would be enough.
Questions only have 5 tags max. If you put a tag on your interested list, the very fact that the row in question is highlighted should be indication enough to remind you which of the tags in the question is calling for your attention.
Unless, as implied in comment, you have so many that you don't know what's in your list anymore.
Alconja wrote a greasemonkey script for this