I think this is good advice, and you're hitting on one aspect of my aforementioned 'productive mania'. When I started programming, I almost immediately went into building projects I was interested in, would use personally, and friends would use. That probably hard a big impact on why I was SO driven, SO productive, and SO energetic.

I try and work on projects like that nowadays, but I can't hit that extreme level of productivity and excitement. It seems that another aspect of that mind state, was that the 'newness' of programming coupled with the success I was having at it BUILDING something, brought heightened mental activity.

I just wish I could tap into that nowadays. Unfortunately, it seems like the brain comes alive most, in a novel environment.