Whisky and Saliva (aka spit)
Okay kind of gross I admit but I bet not to many tasters think of this (at least I haven't seen it or read it yet). When we get ready to put a dram up to our mouth to do a taste you never hear mention or suggestion of clearing your saliva first. The mouth has natural tendency to wet up as the dram approaches critical point of taste (like a pickle that knows its going in). If you have a mouth full of saliva churning up in anticipation of taste wouldn't the salt in the saliva throw off the taste buds? Seems doing a swallow (or spit) of excess saliva just before should be the norm in tasting to avoid excess salt or tweaking of flavor.
And some scotches really seem to create excess saliva AFTER a taste so subsequent tastings would themselves be slightly skewed.
ps - I'm still new to all this and picking up as I go along