I'm gonna start with my worst:
I auditioned for this 'semi-professional' band that claimed that it was heading towards the recording stage of their musical journey and all they needed was avocalist as their former one bailed.
So when I went in, they were pretty cordial and nice but then it was time to "audition". So they asked me what I wanted to sing and I listed out a few popular songs... none of which they knew how to play. I'm talking about songs that practically all of us have hears one time or another (U2, Bon Jovi, GnR).
The only song that they did know how to play sounded nothing like how i remember the song should sound (maybe its just me). Needless to say I did not join the band (or I wasn't selected).
In their defense I checked out their previously recorded songs on Myspace and they were pretty awesome (to me at least). But just as a reminder to bands that audition, prepare a song list of songs that you can play decently which will let the auditionee at last know what to expect and prepare and even get a feel of the kind of music the band is comfortable playing.
Just my 2 cents. No intent at flaming any band just a personal exprience. Peace.