Patience
Patience serves as a protection against wrongs as clothes do against cold. For if you put on more clothes as the cold increases, it will have no power to hurt you. So in like manner you must grow in patience when you meet with great wrongs, and they will then be powerless to vex your mind. - Leonardo da Vinci
Patience is the virtue that lets you handle not getting what you want right now. This happens a lot and people don't always handle it well. Our society seems to be getting shorter attention spans as we move toward an 'instant gratification' ideal. People have forgotten that instant gratification is not a right, its a privilege. How long does it take to learn patience? Always just a little bit longer.