I don't know about you, but I like stability. I like a set routine and I like having friends stay with me for as long as they can.
We have possessions to which we hold on and relatives that we cherish.
Still- we live in a changing world. When the changes in this world involve friends moving away, relatives dying or treasured possessions being lost we feel unhappy. Our natural mindset is to resist this kind of adverse change and we find that the longer it takes us to accept it the longer it takes for us to move on.
Kata, Taolu, Randori or any form of set practice in martial arts feels comfortable when it has become familiar to you. We know, however, that a good kata performer is not necessarily a good fighter.
The reason for this, of course, is because fights are dynamic. Your opponent's timing is not always in sync with yours (although Aikidoka strive to have you synchronise your timing with that of your opponent) and positions, attacks and defenses change.
You can easily see if a fighter is resistant to these changes. He is the person who lets punches get past his defenses. She is the one whose attack misses and does not follow through with another move.
This- is how the practice of martial art brings you in harmony with the world. That same mind that is one with the opponent and the battlefield is the mind that is in harmony with the changes that occur in our lives.
The Universe itself is alive and dynamic. You need to be the same in order to keep up.