A computer has memory which allows it to do useful things. We call this memory RAM, for Random Access Memory. It knows how to prioritize its RAM to work on the most important tasks at a given time.

A human is like a computer. We do things that require thinking, sometimes over long periods of time. Some tasks that take sustained thinking include working on a difficult math problem, figuring out a way to implement a piece of code, or studying for a test. If we load up our active working memory with one task, our brain processes it in the background of our subconscious. We have a computer working inside of us even when we are not actively thinking.

Many things in life are distractions from thinking. Anger, for instance, overloads the less evolved parts of our brain with powerful hormones that take resources away from our RAM. If you want to get something important done over a period of time, you need to defend your RAM.

A quote from Richard Hamming, in You and Your Research:

So the way to manage yourself is that when you have a real important problem you don’t let anything else get the center of your attention—you keep your thoughts on the problem. Keep your subconscious starved so it has to work on your problem, so you can sleep peacefully and get the answer in the morning, free.