How about this one.
When someone makes the mistake and asks you about speaker recommendations and you sit them down for an hour lecture.
I do that, and I don't even own Salk speakers. 
I do that as well, they ask for suggestions you tell them about 1000 things, then they don't listen arrrg.
I've realized that most people I talk to really just want you to tell them that it is okay to spend $300 on a HTiB no matter how much you teach them. I just can't do it.
I told some friends over lunch last week that I sold off my whole 5.1 system to go stereo. They about laughed at me. I preached to my one friend for quite a while months back to just get a good pair of speakers and build from there over time rather than spending less on more speakers. Of course he ended up not taking my advice and is dying to now go from 5.1 to 7.1 in his tiny room. Sigh....
All I can say is THEIR LOSS!