I am sure there are some really good ones.
My question comes to mind because of a recent interaction with one of he tanks in our guild who no call, no showed on a thursday while we were working hard to progress in time to gain the feat of strength for the guild prior to 5.2 release.
The player in question was frantically texted by a number of his co raiders to be told "I am going to visit my mamma for the weekend". Whether this was really why he dissapeared or not we all assumed that meant "going to see his girlfreind".
This weekend we were forced to pug in two different tanks on two new progression bosses for us because he dissapeared again stating this time he was out for the weekend to get laid. Needless to say at this point one of the pug tanks may be changing guild tags and the player in question will no longer need to make excuses for missed raids.
Once during our progressin back in Naxx days one of our healers mid raid stated that her parents told her she needed to go to church with them RIGHT NOW. The joke forever after was "surprise church".
I am just interested in hearing some of the reasons why YOUR players have chosen to explain why they have become less than dependable at raid time.