One annoying type of message that continues to throw me off my game is those brief “okay” and “thank you” messages, especially from staff. I've been getting increasingly good at anticipating these and affixing NNTR or NN2R to my preceding message. Amazingly, both the former and the latter are indexed in Web dictionaries, which makes me wonder why people don't use them more. [That's “No Need To Reply”, natch, not a Myers-Briggs indicator, though it might as well be.]
Anyway, I do, and I encourage you to as well.
Meanwhile, you ask, what do you do? I'm afraid I still send those replies to staff members, because I think it's just basic etiquette (though many a misplaced good intention has been born there...). I'd like to ask them someday whether they'd be offended if I stopped doing this and instead used that old classic from the days of Usenet: TIA (that's “Thanks in Advance”, for you wee ones).