I don't have any better reasons for "ending up with" my tattoos than Matthew does, but I'm not going to apologize. There was a good reason for the first (I think), and it was just sort of inertia from there.
My first was a celebration. As a brand new graduate student at Texas A&M, I had just completed my first of many hardcore summers of turtle research. In this case we'd just wrapped up six straight weeks in the field around Padre Island, on the water or mending nets every day from sun up to sun down. I was tired, but feeling extremely proud, and I had promised myself a treat when we were finished. At the time of the promise I didn't realize the treat was going to be a tattoo. But, you know, there was this girl, etc, etc... plus I was feeling a bit salty.
After we had wrapped up I took a walk a block over from the motel where we were staying. I had heard that there was a guy that had a shop nearby and that he was a pretty good tattoo artist. I'd also heard that he was a bit crusty, but I wasn't quite prepared for peg-legged Pete. I don't recall his real name, but he did have a peg leg. The shop was a pit, but I had already made up my mind, and having actually walked into the place I wasn't going to turn around and walk out.
I told him I wanted a turtle tattoo on my back (what the heck was I thinking, like Matthew I can only see it in the mirror). He asked me if I had any pictures of what I wanted. I didn't, but he happened to have a bunch of travel magazines laying around, which often have lots of turtle/dive pictures. I wanted a really nice green turtle on my back (that's what I was studying at the time), photorealistic was what I was thinking (what did I know). I couldn't find exactly what I was after, but there was a loggerhead in the sort of pose I wanted. So I told him that was what I wanted except "make it look like a green turtle." I told him about the pretty scute patterns that juveniles have and showed him a couple of crappy shots from the magazines. He said he had it and got to work.
When he was done it was hard to tell exactly how it turned out. It was on my back afterall, and the area was a bit bloody and swollen. So I decided to give it a thorough going over later. We had to pack and go home. By the time we got back to Galveston it was well on it's way to healing and I could clearly see that I had forgotten to mention at least one critical item to him. That being that green turtles have much smaller heads than do loggerheads (duh) relative to their bodies. So it kind of looks like a green turtle, except with a really massive melon! Hard to tell these days as too much sun and other bad habits have muddled the picture a bit.

In any case, it was all inertia after that. In short order I ended up with a few more tattos (only one of which can truly be attributed to alcohol!). No more turtles, except that I did have the kanji symbol for turtle tattoed on one arm (guess what you can chalk that one up to). I eventually went to a local guy in Galveston to have my turtle cleaned up a bit. There wasn't much he could do about the head, but he did add a bit of color, and charged me about twice as much as the first guy.
The moral of the story... I have no idea why, at the age of 35, I am sitting here in front of my computer talking about my tattoos. I was wise enough to place them all so that they could be easily covered as needed, not that's it's ever really an issue. If I had it to do all over again I probably wouldn't change a thing. It was a lot of fun at the time and makes a great story for my kids (Hey daddy! There's a turtle on your back. Yes dear, I know).