Be willing to give up that you know something for certain. If you check in with others to validate you will for sure find as many others who believe something else as well as what you believe.
Just maybe you can lose that weight, run a race, get that job. Whatever it is, suspend your judgment for a bit and consider if the goal is something that would make a positive difference. Who knows, just maybe then you'll be doing it!
I learned this as a breast cancer survivor, rehabbing a broken ankle, losing 35 lbs & learning to run. Next week I run my first half marathon! I've fought hard through it all but the real gain came from thinking just maybe I'm wrong when I say I'm not up to this. I am and you are too!