I'll bite...
You know you are a sad elitist when...
... you do 200k+ dps on bosses, but 100k on AoE trash.
No way anyone with the gear to do 200k dps don't know their spec's AoE rotation, they are just dragging their feet because they can't be arsed to play properly on trash
... you have your HC geared tank hybrid as a DPS role and bitching about bad tanks in LFR.
If you are so pro that you know exactly how to tank you have two options: 1) offer relevant help, or 2) queue as f'ing tank yourself.
It happens so often that those tank hybrids show up in their 570+ dps gear in ToT stroking epeen on the meters and yelling at the tanks. What are the odds that if they know so much about tanking that they do not have a tank set of at least 500'ish sitting around? (heck, stats are no biggie these days, tanking in 570+ dps gear with dps enchants and gems is perfectly viable).
But sometimes you can have the opposite reactions as well. Or maybe the EU servers are just less rage'y...
The other day I brought my guardian druid (ilvl545) to vaults, because a friend needed some sigils to get the legendary quest going. And queuing two people as tank+dps goes a lot faster than one person queuing as dps on his own. I did top dps, and top healing (I ran with dream of cenarius and have a mouseover HT macro - so was spothealing the raid while tanking). I had two separate people whisper me "why are you here?" (or probably more accurately: why u here?!). To which I responded: "helping a friend" and they let it be with a "oh, cool".
Maybe the one elitist sin I am guilty of is being really amused when the bad players don't see they got carried. I distinctively remember a SoO wing1 group I was in with my drood healing. They barely made immerseus and I think I was the only one actually healing the blobs. The group was BAD, almost wiped on pre-immerseus trash kinda bad. Then the customary caster left after immerseus and we got a lock in for protectors. This guy pulling 1M dps protectors and me doing 90% of the healing and afterwards everyone is going nuts in chat about what a good job that was. Tanks both got CR'ed twice, half the raid was dead, and without the lock it would have been an embarrassing wipe. Funny part is, nobody was sucking up to the lock, so if he was there to stroke epeen, he must have been pretty bummed.