On a point of clarification, I commented on the "Mike Tyson's Face tatoo" list item that  I think this one could be expanded to a more generalized "It makes you look like a dumb-ass."

The wrong tattoo certainly can accomplish this...

Let me relate a small counterpoint here. I have had a tattoo since I was in my late teens, of a spider on my left arm. I got it for no good reason, and have never particularly regretted it or considered having it removed.

Let's fast forward a few years to when I started working in politics and advertising. There were moments when I would take off my suit jacket, roll up the sleeves of my monogrammed shirt and take note of the reaction of my more whitebread companions. In that environment, the sudden exposure of the tattoo, together with my penchant for direct and sometimes pungent language was often a decided edge.

Having said that, I think exposing two full arm sleeves of tattoos or having them crawling out of your shirt and up your neck, in similar circumstances, would get you put in the dumb-ass category, as opposed to the slightly unnerving category.