The title pretty much says it all. It simply isn't healthy to obsessively compare your own life with that of someone else’s. This is probably the most important piece of advice I can give, and one of the ones that I find least followed. Hell, I fail to follow it all the time. But the fact is that comparing yourself to someone else is just a waste of your time and mental effort.
There are plenty of fitness celebrities out there online. For each one, there’s absolutely tons of pictures or videos. Fitness celebrities have to market themselves, have to make themselves visible, and the best way to do that is to take pictures of themselves without shirts on, or busting out a heavy weight. No one is above that. But the problem is that I constantly see people compare themselves to these athletes in a negative way. People look at Frank Medrano, Simeon Panda, Jay Cutler, Arnold Schwarzenegger, or any other athlete who has been training for years and years, and they immediately want to look like them.
Worse, half those crappy “look great in fifteen minutes a day” programs that you always see advertised on the web usually accompany themselves with pictures of these fitness celebrities, as if they didn't simply steal commonly available images and as if these celebrities actually endorsed their programs. It shouldn't need to be said that these guys crafted their physiques through years and years of difficult training and careful dieting. The only way to look like those guys is to train like them, for as long as they do.
Why should you let that get you down, then? People work out for a few months, get disappointed when they don’t look like Arnold, and then quit. If you really want to look like Arnold, you need to stick with it like he did. Further, you need to learn to place realistic expectations on your development. Just like you can’t expect yourself to get a college degree overnight, you have to realize that getting in shape is a massive investment of time across years. So long as you stick with a good program consistently, you’re going to look good in ten years no matter what, even if you aren't pushing yourself to compete. So don’t let lack of progress in the short run ever get you down. Don’t compare yourself to others.
To be fair, you do have to compare yourself to others, if you’re going to have any real conception of your progress. Take pictures of fitness celebrities and use them as guidelines for your goals. Work on your arms for a while, and then get your legs up to par, or vice versa. Work on your physique slowly and methodically, and switch up your training just enough to keep it from getting stale. Pictures of other celebrities can help you understand where your weaknesses are so you know what to target and improve. But every body is different, and just because Arnold had great biceps doesn't mean you can make yours look exactly like his. Learn your strengths, play into them, and alleviate or cover up your weaknesses. Use others as a baseline or guideline to work from, but not a rule.
This advice applies to every area of life as well. Don’t be that guy who graduates college and instantly gets sad he isn't making 75k a year like some 30 year old he knows. You've got eight years to get there, don’t compare him to you as you are now. Set your plans to be where he is at his age, and only criticize yourself if you don’t make it in the same time span. Success isn't a linear increase, but rather a sketchy and confusing jumble of ups and downs. There's always a good chance that guy you know will lose his cushy job and suddenly find himself making significantly less within a short time span.
Don’t compare different kinds of success, either. Maybe your job of choice isn't a huge money maker, so learn to appreciate what your career path does earn you rather than wondering why you aren't making all the money in the world like some asshole banker on Wall Street. Comparing yourself to your friends is particularly toxic, because they’re all your age and thus they actually are at a similar stage in career development to your own. Just because one of your friends succeeds early doesn't mean he’s going to be succeeding later, and just because you don’t have your dream job right now doesn't mean you can’t find it. Once again: compare yourself to others only as a way of setting a baseline to push you further. Don’t wallow in negative fears about the long term simply because it might seem like others are doing better than you in the short term.
Set success on your own terms. Set goals for yourself and push to reach them. Use others only as a way to establish your goals (in the professional sphere, of course, not on a personal level) and provide motivation to pursue them. Harsh judgment isn't helping anyone, especially not yourself. In the end the only thing that matters is how you feel about your own success, and if you're proud of yourself, then don't ever let anyone get you down.