It's never been easier to find ways to be disappointed in our performance. You can compare your output, your income, your success rate to a billion people around the globe… many of whom are happy to exaggerate to make you even more disappointed.
It's hardly worth your trouble.
The exception is the dissatisfaction that is based on a legitimate comparison, one that gives you insight on how to improve and motivates you to get better.
Get clear about the change you're trying to make and, if it's useful, compare yourself to others that are on the same path as you are.
If the response rate to your website is lower than your competitor's, take a look at what they're doing and learn from it.
If your time in the hundred-yard dash is behind that of the person to your left, analyze the video of their run, step by step, and figure out what you're missing.
You can always find someone who is cuter, happier or richer than you. (Or appears to be). That's pointless.
But if you can find some fuel to help you reach your goals, not their goals, have at it.