"Oh wow, you had someone scar your flesh with ink, you are SO COOL. Are you going to get a faux-hawk next week?"
Aw, I think faux-hawks are kind of cute. They are hair cut to multiple different lengths, therefore they are fun to play with, tough-looking or not.
But anyway.
I can think of no idea so important to me that I would cut it into my flesh.
I can think of plenty of ideas that are important enough to me that I would cut them into my flesh... if it seemed that doing so would somehow benefit the ideas, which it doesn't. I just don't think a tattoo would feel like a particularly meaningful symbol to me, regardless of what it was. I can definitely appreciate that others find them meaningful. It's a lifelong commitment, sometimes beginning with a very long and painful ritual, and I can respect people who go into it thoughtfully, choosing that method not just to express their deepest values, but to dedicate themselves to those values by signing over a piece of their body. I can respect those people even when the value they are consecrating is simply the aesthetic of the tattoo itself, because aesthetics are important. I agree that doing it to appear badass or to get a reaction out of people seems silly, but I can believe that many people who get tattoos do it largely for their own eyes, so they'll see the tattoo every day when they wake up and when they go to sleep, reminding them of whatever they wish to be reminded of.
The reasons I don't expect to get one, though, are firstly that I haven't been very successful at distilling my favorite ideas into individual symbols. I've occasionally thought of getting a math tattoo, but my idea for what to include in the image changes every year as I learn more and my focus changes, and I don't expect that to stop. And secondly, as I said, I don't think I would find the medium meaningful. At times in my life I've thought to consecrate ideas by wearing pieces of jewelry to represent them, but this eventually results in the jewelry feeling like a burden, and to me being increasingly struck by the fact that the jewelry is an object and the idea is not. I think that even if I had a single idea that drove my life above all else, and a perfect symbol to represent it, if I ever had it scarred into my arm I would look at it and think, "This was already written more eloquently in all of my cells, in all of my thoughts, in all of my actions. Why did I need to write it on my skin?"