The Interesting tab mostly shows questions tagged with my Favourite Tags. However, it also shows the odd question not tagged with one of my Favourites Tags.
It seems very unintuitive behaviour to me; a little like if we were to include questions with no bounty on the Featured tab.
See the screen grab below for an example: questions tagged jquery and jqgrid are appearing even though I have neither of those tags in my list of favourites.
Is this a bug, or status-bydesign?