One guy shows up (late), to play with a woman who had signed up as well as by himself. Older guy. QUite a good guitarist, but that's beside the point.
I was playing guitar for a singer and he come up to start messing around with the mixing board after her first song. I quickly pushed his hands away and asked him what he was trying to do. I adjusted the EQ (barely) and after he said 'much better'.
Then when I was setting up the woman he was going to play with, he didn't want to use my guitar cable, wanted his own. Wanted to plug straight into the board instead of my DI box. Wanted all sorts of adjustment on the EQ. Hogged the keyboard away from the woman on her 3rd song!
After they were finally done, there was one more player, and this same guy ran up to the 2nd mic and started singing backup, and when the song ended this guy was trying to get the player whose song it was to keep going, he kept singing.
I started a second round of songs (but THAT guy was not getting up again!) An older guy was doing his 2 songs and this guy grabs his guitar and goes to plug into the board, I ran up and told him 'no', but he continues on to the seat that was back there and was going to try plugging into the bass player's amp! I got in his face and said 'NO!" What don't you understand? No!' and he went back to his table and sat down.
At the end of the night, I was packing up (all my loose gear was on one table) and he came walking around saying he had lost his reading glasses. I finished packing up, loaded out to my car, came back in to make sure I hadn't left anything and my spare mic pouch with a Sennheiser on it was on a table over to the side where this (same) guy had put his 2 guitar stands and some other things. He says innocently, 'Is this your Sennheiser?", I grabbed it and left - there is o way that mic was ever anywhere except on the table with my gear, so he must have grabbed it when 'looking for his glasses'. F*cking bastard!