My worst tattoo experience was dealing with an artist who was a heroin addict. This guy was an addict, but he did awesome work. Mainly (over the years) the only problem was he had dozed out a few times and I had to leave because he was to messed up.
The main event, was one day I was getting work done, and about five cop cars pull up to the parlor, jump out of their cars and bust in to arrest my tattoo artist. Not only did my work have to stop but the guy ended up getting sentenced to 5 years in jail for armed robbery.
He had robbed a liquor store to feed his growing addiction. I never saw the guy again and had to have another artist finish the seascape theme on my back. That sucked because like I said, the dude has massive talent.