Well worth a half hour if you can pry one loose.
There's a bit near the beginning where Glennie talks about how if you hold a drumstick too firmly you both wear yourself out and don't get a good range of sounds from the drum. It occurred to me that this might be a good metaphor for dealing with people. If you try to have too much control of your interactions, you wear yourself out and don't get the best responses.
Link thanks to sanguinity here.