In 1972 the TV pilot film "Kung Fu" starring Keith Carradine, was released; in the first seven minutes of the film a great lesson is imparted to those paying attention. Caine, the role Carradine plays, reflects back on his beginnings as he walks through a desert setting. Caine recalls waiting outside a Kung Fu Master's training hall as a boy for weeks, no matter the weather, and without distraction, in hopes of one day being invited into the training hall. One day, Caine along with a few other boys are finally invited in and the boys are seated at a table in front of the Master who is already seated. Tea is passed to the boys and then a cup is given to the Master by his assistant. The Master appears to begin drinking, but he stops, three of the four boys begin to drink and follow through on it. The Master's assistant dismisses them, but tells Caine to stay. Caine did not drink the tea and the Master asked him why. Caine replied, "After you, honorable sir." Caine's manners and humbleness cinched his access to a new way of life.
While potential students would never be expected to stand outside for weeks on end to show they are worthy of a place within the International Karate Association & College of the Martial Arts, it is expected that every student demonstrate a degree of humility as only through being humble can one truly learn discipline and self-control. If you are not humble or cannot attain humility -- you are not teachable.
Martial arts require discipline and self-control; without these attributes, people get hurt and an ancient structure that has been built on respect is reduced to chaos. As students work their way through the ranks and become more and more proficient in their techniques, it is easy to develop an inflated impression of oneself and it is at this time that you will have initiated your own downfall.
How do you keep your ego in check? Stay humble, it will keep you grounded. Studies have shown that humility stimulates intra- and inter- personal attributes that facilitate self-regulatory abilities[i] and this is what you want to strive for both in the dojo and out. Accept criticism, help around the dojo, participate in soji (cleaning), help lower ranking students be the best they can be -- be a role model. If you feel a task is beneath you, you most definitely need to do it, otherwise, this is not the place for you.
Having humility will get you closer to perfection than having great technique alone ever will.
[i] Humility Facilitates Higher Self-Control, Eddie M.W. Tong, Journal of Experimental Social Psychology, January 2016, Vol. 62, Pg. 30-39