I have a childhood friend who became a doctor. Everyone admires him. He's a good dude and deserves it.
But I often find myself feeling like I wasted myself by not pursuing medicine; I had the grades. Instead I've pursued illustration. I haven't made any seriously good work, but that's not what bothers me. I often wonder " what if illustration was a less worthwhile pursuit, right from the outset? What if I made the very best works possible in illustration-- they're still not saving any lives.
I found a lot of comfort from that just now with the thought: "what if Bill Watterson had chosen medicine?"