If you ever spent the day ground-n-pounding a heavy bag, sledge hammering tires, pad work, sparring..... you quickly realize that you can become an aggressive *******.
My master always encouraged playing an instrument, etc. I like surfing, to mellow and balance you out.
I think this were the Buddhism, Taoism came into play with ancient warriors.
However, to focus on the spiritual side and not train the martial, equally leaves one out of balance.