Well these past few weeks for me have been horrible tea-wise since I've had a sinus infection. It takes away a lot of my tasting abilities, but does anyone else have annoying things that hurt their tea-sensing abilities? I have two more that just happened too:
scratched up the roof of my mouth with crusty bread burnt tongue
I find that pungent spices like garlic, onion, chives can really bring out certain unpleasant characteristics (excessive astringency) and dampen more pleasant ones. Especially with greener oolongs, I find that these flavors make it harder for me to taste tea properly for quite a few hours.
Rich T mentioned once that a tea seller told him that banana makes teas taste better than they actually are.