Zen story: Yamaoka Tesshu was one of the greatest swordsmen of his time and was a layman who had almost embraced true mastery in Zen. Yamaoka Tesshu, as a young student of Zen, visited one master after another. He called upon Dokuon of Shokoku.
Desiring to show his attainment, he said: “The mind, Buddha, and sentient beings, after all, do not exist. The true nature of phenomena is emptiness. There is no realization, no delusion, no sage, and no mediocrity. There is no giving and nothing to be received.”
Dokuon, who was smoking quietly, said nothing. Suddenly he whacked Yamaoka with his bamboo pipe. This made the youth quite angry.
“If nothing exists,” inquired Dokuon, “where did this anger come from?”
Mastery takes many decades if not a life time of study and perseverance. Any person who says, "I am" is probably not. Aikido is the same way. To master it is to realize its greatness. In realizing its greatness, we are realize the vastness of what we don't know and are humbled. It is like the parable of the rice stalk from Kodo: "The young rice stalk stands straight, proud and strong. As the rice stalk matures and becomes wiser, it "bows" its head towards the earth in humility and respect." So true indeed. If one wants to show true mastery, don't talk about how much you "know," but instead demonstrate how much you don't know with humility and humbleness.