It's a sort of parabola. No tats? Fine. Tramp stamp? Bad. A dozen 30 minute doodles of random shit? Stay the fuck away. One giant back tattoo? Can be surprisingly fine.

There's an interaction of self-control and commitment going on. The ones who make hasty decisions that are permanent and require no follow-through that are the absolute worst. The ones who sat under a needle for 50 hrs on one piece because "I really like dragons" might be a bit off, but in a different way.