Banzai is one of Scar's loyal Hyena friends. Food really motivates him, in a way that surpasses the mere devious hunger of the other Hyenas. Hunger, and a sheer mean streak, often cause Banzai to do extremely stupid, and painful, things. If Shenzi didn't keep him in line all the time, he may not have lived to be this old.
In fact, it is very likely that he would have eaten Ed. Whenever Banzai does something painful or stupid, Ed is there to laugh at him. This really ticks him off. He and Ed fight a lot.
Banzai doesn't think things through enough. It's a good thing Shenzi is there to keep him out of trouble, but even her valient efforts can't prevent Banzai from looking like an idiot. One credit to him - it never takes long for him to recover the upper hand.