Thanks for reposting! I had a look and found the document... The brain also loves: - To work on our problems in the background (e.g. forget about the problem and go for a walk, you might have a solution by the end, or better perspective at least) - A certain level of complexity and challenges - A certain level of organisation and structure in our lives - And finally to play (speculate, imagine, invent - this is why we shouldn't always distract ourselves when we're bored!)