Worked for him when he was CDI - he was grumpy to those who failed to prepare for him properly. He was also very good to us, and there was a lot of loyalty to him.
To this day I feel loyal to him because he took the effort to start my final briefing to him by spending two minutes saying thank you to me for my work and wishing me luck in my next post - which as I was a very junior person, he didnt need to know about or take an interest in. I won't forget that small gesture which meant a lot to me.