Experience. [Been there, done that]
With 15+ Years of experience in design, chances are I've seen just about every problem there is to see. Since I'm still here, I must really love it (or must be really dumb).
Versatility. [Might enjoy doing that]
Heinlein said "Specialization is for insects" and I agree. Working with a vast array of design disciplines, I've learned to wear a lot of different hats. And I hope I can keep finding more (does the hat metaphor work?).