This! I couldn't agree more. I try to end my day at work with a challenging problem that I won't be able to complete. I think about it a bit on the train ride h

This! I couldn't agree more. I try to end my day at work with a challenging problem that I won't be able to complete. I think about it a bit on the train ride home, and then it slowly dissipates throughout my night. I eat some dinnner, relax with my fiance and go to bed. By the time I get to work the next day, 90% of the time I'll come up with a solution in 5-10 minutes that I couldn't get to the day before. Also, doing this gives me a clear entry point into the day and that 'winning' feeling you get whenever you solve a tough problem. I highly recommend it.