One of the books I have is The Dip by Seth Godin. The basis of it is that "overnight success" is more often the result of putting in months, years, even decades of work when the going gets tough to get the little advantages that lead to tremendous success. It is similar to the 10,000 hour idea that Malcolm Gladwell has. The other side of the coin is the dip for some things, like CEO of a company, is so long and deep that many people decide they don't want to put in that kind of work, despite the rewards. In those cases, Seth suggests you should quit. Just say no and move on to the next project where you can get through the dip.
As I think about Mt. Everest, my running, my engineering career, they have all had many setbacks. Yet I feel that getting through the dip is worth it. Tonight I slogged through a set of track intervals while a college student led them all. I suffered. My back filled with lactic acid, that only happens when I am truly filling my body with that uncomfortable substance. It hurt. Part of me wonders why I am putting myself through this at 27 years old? Yet I know that getting trough this workout, and the next seven just as painful will lead to better performances than I have ever had. For me, if I can raise the bar even just a little, just a few seconds in a race lasting a number of minutes, there is success.
The point is, if you actually want to go after big goals, you are going to get hurt. You are going to suffer in the pursuit of better. If it was easy, everyone would do it. Apple has success because of the relentless pursuit of perfection. Galen Rupp wins races and Olympic medals because after setting an American Record he does a still difficult track workout 15 minutes later.
I'm not saying suffer through every setback. Sometimes it really is worth quitting something and spending your time on things more worthy of your time. However, there will be setbacks in the things you set out to do, and you have to get up and dust yourself off and keep going. Learn from your mistakes and don't make them a second time. My setback and lesson of the week: sitting makes your gluteus muscles fade away and if you want to run fast, you have to strengthen and stretch them otherwise you will end up with knee pain.