Elon Musk may have complained silently and to people very close to him, you have no way of knowing, he complained, but did not do it openly and did not stop. You can complain, but do not decide to quit after complaining. You also need to be careful about the person you complain to, because complaining to some people who are good in discouraging people from achieving their goals can get you to get discouraged from doing more. There are some people that if you complain to them they will console you and still encourage you to find a reason and way to continue to reach your goal while some others will discourage you and tell you that you have tried and you need to rest. You need to run from people who discourage you from reaching your goals whenever you complain to them, the people who encourage you to keep going and never quit are the people you should keep around.