@richking58 So I think I’ve visited a similar cafe (assuming it’s a franchise). I can see why you thought you were doing the right thing, but I will pass on some tips that’ve helped me.
First, after both cups are poured, make sure you give your cup back, and you take the owners cup. This establishes that you believe both cups are free of poison.
Now, though you might think slurping is right, (since tea is a liquid) you are wrong here. You must make the same consumption sounds you do for ALL food items, so more of a “mm mm mm” nibble sound.
If at this point you haven’t been kicked out yet, it is now customary to offer tea to the owners best friend, her Jellycat. You must also make the consumption noise on behalf of the animal, but this can be a slurp.
At this point in the tea ceremony, the young landlord (sibling) will come in and raise the rent, demand you get rid of the teapot, and generally change the entire game. For better or worse depends on the age of the landlord.