An extremely valuable skill for a warrior is to develop a sixth sense to feel when he is going to be attacked even though there is no physical indication or warning. This is called "sakki" (murderous intent).
One afternoon several of us were at a party at Saito-sensei's house. I was sitting next to Sensei. We were all relaxed and having a good time.
For some reason a crazy thought popped into my mind. If I spontaneously attached Sensei, would he be able to react? Of course I would never be stupid enough to actually do it. I was just thinking "what if?".
Then Sensei looked at me and said, in Japanese, "David-san, training is training and a party is a party".
That completely blew my mind. He pre-empted my thought. If there was any doubt that this is exactly where I wanted to be (actually there wasn't) this totally confirmed it.