Glory
Over the years, the members of the band become like your family. (Maybe closer than family, as your own family might say.) You're the first person on the drummer's speed dial, and you're the first person the bassist calls from the jail cell. So it's probably safe to say you like these guys or gals, you like the music they produce, and you're proud to be their manager.
Every deal you negotiate on their behalf, and every performance that brings the house down, is a personal victory point for you, too (and also a serious ka-ching in the bank account). All those victory points can add up to one stellar reputation that can propel you to bigger and better things. Whether that means moving on to a new band to manage, or just using your skills to help your current band do better every day, is up to you.