The 'point' of the tea thread, if it must have one (and lets face it, a lot of threads don't really) is for anyone who fancies to, to drop in, natter aimlessly for a bit about whatever happens to crop up, and then drop out when they fancy - a sort of common room. I think it's sort of like a condensed CycleChatCafe - fewer people, and perhaps a greater percentage of nonsense (funny nonsense, not stupid nonsense). I didn't venture in much to start with, but I've inveigled my way in, and I love it now. In fact, I think I've made a good friend through hanging out in there.
And unlike a lot of threads, there is rarely, if ever, any abuse. Ok, we did all gang up on someone a bit yesterday when he fell asleep and we played Buckaroo with him and all the furniture, but he took it in good heart...
If every thread has to have a point, like Waffleycat says, I think it would be very dull.
With regard to the worst tea/coffee bought - there's was cafe, about 10 years ago now I suppose, attached to a craft centre in Bonar Bridge, on the East Coast of Scotland between Inverness and Wick, where they served drinks labelled Tea and Coffee, but which were both, as far as I could tell, dishwashing water...