It means that Thursday evening, when you're tired, it's easier to pick yourself up and work, because doing so gets you a _better_conversation_ on Saturday. I'm a cellist - this comes from private music lessons (and also karate).
See also http://en.wikipedia.org/wiki/Bloom's_2_Sigma_Problem . In that study, the median person learning one-to-one performed at the 98th percentile in a control group. That's huge!
