The comment about excelling really rubs me the wrong way. I wish he would check finishing times for some local races, see how much the powerlifters at his gym are lifting, or visit a local Crossfit affiliate. Where did he get the idea that it is so easy to "excel" these days? The word can be used without an object, but it is inherently comparative. The gym provides me a lot of satisfaction and physical benefits, but comparing myself physically to other people is a not a benefit but a pitfall. It's the one thing at the gym that can ruin my day. "Why do I come here? I will never be like that guy... or that guy... or that guy." I will never be 6'4" and have an eight-pack. I will never squat 500 lbs. I will never have a killer Murph time (look it up.) I will never qualify for the Boston marathon. Well, that last one I could perhaps do, but only by giving up many other things I value more highly. The impulse to excel argues against working out the way I want, which is to work out three times a week and enjoy the health and appearance benefits.
So I will continue to go to the gym, reap the benefits, and try to keep my impulse to compete in check. Be warned that excelling is not something you simply decide to do as a third or fourth passion. It's best not to compete and expect to win against people whose first priority is fitness when your first and second priorities are something else.
I agree that comparing to others is mentally unhealthy. This applies not only to the gym/fitness but all areas of life. On the other hand, measuring progress is a good motivator, and I feel a proper way to do that is to challenge yourself. If you were able to shave X seconds off your mile time, or improve your squat weight by Y pounds, then I feel it is a proper motivating factor as well as one that could assist in keeping your mental attitude in the right place when other facets of your life are troubling.
I believe comparing yourself to others can be healthy, as long as you don't let it get out of control. How else do you know what's possible? If your friend is progressing much faster than you, almost certainly he is doing something different than you are. If you weren't keeping track of him as well, you might miss out on chances to improve.
If everyone was just racing against themselves, I really don't know that we'd ever have seen a 4-minute mile.
So I will continue to go to the gym, reap the benefits, and try to keep my impulse to compete in check. Be warned that excelling is not something you simply decide to do as a third or fourth passion. It's best not to compete and expect to win against people whose first priority is fitness when your first and second priorities are something else.