God has gone before you. He knows your end from your beginning. He knows all the days of your life. In his great foreknowledge, he has gone ahead of you and planted these flags ahead of you. Paul even states how important it was for him as a leader to be sure that his own life reflected strong self-control while he has preached it to others or he himself could lose the prize.
Real leaders have a great deal of self-control in their lives.
Such self-control should be evident to all. Israel serves as a great example of the possibilities of self-control, and the results when such control is absent. All the Israelites had experienced equal realities, both with God and each other and so many of them perished through failed self-control. They now serve as a warning to us to not follow such an undisciplined life. Generally speaking people who complain a lot are usually undisciplined people their complaints help them excuse their own lack of self-control by putting the blame on others.