Thanks to all. This problem has inspired me to learn more about the Standard Model. I'm sure that there has to be some explanation for the masses of fundamental particles, and there's a good reason why it isn't obvious as yet. It is however unlikely that I'll appreciate even the question fully...
Thanks for the answers! Let me rephrase the question: is there any explanation for why known particle masses seem to get big in a hurry? Why does it look like an exponential increase, and yet it isn't?
For simplicity I was thinking a one-dimensional plot - just the masses. What I see is that (mostly!) the differences in mass between each known particle appears to dramatically increase as you go up the energy scale. To get this into a 2d plot I guess you could sort the particles by known mass...
Looking at the known masses of the elementary particles, they appear at first sight to be on some kind of exponential curve. It is certainly attractive for there to be such a simplicity - however, and interestingly ...nothing really lines up exactly. Is there any explanation for this or for the...