Coaches do so much research about a referee because they believe refereeing is such a crucial part of the game that the result may hinge on what we say or do. They probably know more about me than I know myself!
I do my own analysis on the teams I am refereeing. I will know some of the personalities, the players who could be difficult customers in a scrum situation, the ones I am going to have to really work hard on early in the game to get what I want.
I could give 48 penalties in every match if I wanted to. It is a question of sometimes choosing what is - in your own mind - of material importance and what isn't, what might be a crucial potential penalty and what might not be.