I think it's a shame that you can't relate positively to someone who is ahead of you. Sure, use them for motivation. But I fear that you don't have a real healthy basis for your own self-esteem if you have to be bigger and more cut than everyone in the world in order to be happy about yourself. You need to accept that there will always be someone better than you in any criterion you choose to consider. But you are also better than everyone you meet in some way. Way better for you to go introduce yourself, shake their hand, and swap training tips!
This is very good advice, and something i need to keep in mind, myself.
To further expound upon this point for the sake of CorlessJohnJ (and for my own): There's no use raging against genetics, nor is there any use thinking "I could've started sooner, I could've worked harder". That stuff is all formed. Feeling bad won't make you stronger, only work will. Better instead to use that energy to motivate you in a positive direction, to do today's workout, to finish THIS set, to move THIS weight.
I find that i'm never satisfied if i compare my own achievements to the achievements of others. None of us is completely immune to such destructive thought processes, but i think we can get better at avoiding them, just as we can get better at working out. Rather than allowing yourself to feel diminished because of what someone else can do, just look at how far you've come since you started. Comparing yourself to yourself is the only way there ever was.