Self control is the grace to say "no" or "stop" to yourself when you're in a situation that is tensed-up and it looks as though you don't have a choice. When you have self-control, it means you're disciplined, and then you could make a good leader.
Self control will make you reject bribe no matter how big the amount is. Self control is what restrains you from fighting in the face of physical confrontation. Self control will make a person quiet in the face of verbal abuse.
Self control is not by your power or strength or even by your nature, it is by God's grace.
You too can receive the grace to have Self control, just ask for it. After all, God said He'll give us, if we ask.