Often you will find that the best at anything have a certain humility, this is because in their pursuit of excellence they have realised how little they know and how much more there is to learn. They call themselves students and always see themselves as such, seeking always to learn.
Often those who are the least humble are the mediocre, they have learned a little but cannot see how little they really know. They believe what little they know is all that should be known and become arrogant in their little knowledge. They proclaim themselves masters and never seek to learn.