Ever since I was a kid, I've always built my main rig myself.
The time when that was practical or necessary passed a long while ago, but it was an eccentricity I couldn't ever let go.
Some of it was borne out of the DIY punk rock impulse, some of it out of a sense of craftsmanship, some of it out of overindulgence of a control complex, I always preferred writing code on something that I built myself.