I have three tattoos, all of which I designed myself.
The largest is a loose celtic knot, in the abstract shape of a bird, that spans my whole lower back. I did the design and tweaked at it for two years before I actually had it done. It's big for a first tattoo, but I knew I wanted it, and if I found I couldn't stand the tattoo process, at least I'd have that one. The impetus to finally get it? The realization that I was actually better off without the fiancee who had dumped me the year before, so the bird was a celebration of freedom.
Second tattoo had a much shorter planning period. As an assignement in a college art class, we had to come up with a personal symbol, and I came up with a candle nextled in a crescent moon; and really really liked it. The next semester, I got it inked on my calf a few hours before curtain on opening night of "Cat on a Hot Tin Roof" which I both SMed and Master Carpentered my senior year. Sort of a "Congratulations, you survived!" treat.
The third is the spiral triskele from the Newgrange Passage Tomb, encircled in vines, at the base of my neck. The artist did a great job of matching the colors of the bird.
If I wear work appropriate clothes, none of them are visible, except perhaps tiny glimpses of the triskele through my hair, and even if they were visible, they're all tasteful, abstract geometry. I've had my oldest tattoo for ten years, and I've never regretted a one of them. They make me happy to think about.
But, I do think that's in a large part because I did the design work on all of them, taking my body shape, aging, weight loss and gain, and pale skin into consideration (only the moon has any black in it.) I know I wouldn't be so pleased with them, still, if I had picked them out of a book, and I thought about all of them for at least a few months before I went under the needle.