Once, in Scandinavia, I had a debate with this Northern Irish guy about the proper way to serve tea. He was of the understandable but misguided opinion that digestive biscuits are superior for dunking than rich tea! An onlooking American expressed some bemusement about British tea culture.
But it is important. You have to get it right:
To clarify - I'm of the opinion that dunking is a bad thing, but if you really must do it, then rich tea biscuits are the better choice because they are less crumby.