Picture if you were a camp counselor for a sports camp (archery, survival, football whatever). The first day of camp, you show everyone where things are and make sure they are fed and bunked. Tour of the camp, a couple games, an icebreaker.
The next day, everyone wakes up at 6AM for the daily run and 7AM breakfast. Almost everyone. The people who didn't adjust to the change -- well, there's always tomorrow to try.
A few days later, they go for a wilderness overnight with nothing on their backs but a drop cloth. This is not for punishment, but for endurance training, creative solutions, teamwork, stamina, breaking through fears... all sorts of things. Everyone's weaknesses will show up. (Including the braggart who tramples others' spirits by insisting how great he is.)
The end product is a well-trained athlete.
You could have let the campers stay home and practice the sport on their own, but they would have a very narrow set of skills that way, because they would practice their preferences, their strong areas. You also could have sent the slow ones home the first day, but believed in your ability to hone their weaknesses into strengths. The camp was able to do all sorts of things for people, even when they'd given up on hundreds of other attempts.
Don't give up on yourself when you find yourself weaker than you thought you were -- run the race with endurance, because Others believe in you -- God knows where you are, and has watched everyone go through these struggles and come out at the end.
