Why? Because failure drives you, everytime you fail, you learn something new. Now, if you didn’t learn anything by failing, you probably didn’t fail enough. One of the best lessons I ever learned was that it was OK to fail.
You've failed many times, although you may not remember. You fell down the first time you tried to walk. You almost drowned the first time you tried to swim, didn't you? Did you hit the ball the first time you swung a bat? Heavy hitters, the ones who hit the most home runs, also strike out a lot.
It is OK to make mistakes. Failure has a wonderful way of teaching you lessons, sometimes very painful lessons, that you can use the next time you tackle a problem.
You may not learn the lesson the first time, or the second, or fifth time, but eventually each failure will teach you something you can use later.