Edit 2019: By the spark, was everything I wrote before mid-2018 idiotic? Apparently.

Content warning: a couple LWers apparently think that the concept of ego depletion—also known as willpower depletion—is a memetic hazard, though I find it helpful. Also, the material presented here won't fit everyone's experiences.

What happens if we assume that the idea of ego depletion is basically correct, and try to draw an analogy between thermodynamics and willpower?

Figure 1. Thermodynamics Picture

You probably remember seeing something like the above diagram in a chemistry class. The diagram shows how unstable, or how high in energy, the states that a material can pass through in a chemical reaction are. Here's what the abbreviations mean:

• SM is the starting material.
• TS1 and TS2 are the two transition states, which must be passed through to go from SM to EM1 or EM2.
• EM1 and EM2 are the two possible end materials.

The valleys of both curves represent configurations a material may occupy at the start or end of a chemical reaction. Lower energy valleys are more stable. However, higher peaks can only be reliably crossed if energy is available from e.g. the temperature being sufficiently high.

The main takeaway from Figure 1 is that reactions which produce the most stable end materials, like ending material 2, from a given set of starting materials aren't always the reactions which are easiest to make happen.

Figure 2. Willpower Picture

We can draw a similar diagram to illustrate how much stress we lose while completing a relaxing activity. Here's what the abbreviations used in Figure 2 mean:

• SM is your starting mood.
• TS is your state of topmost stress, which depends on which activity you choose.
• EM1 and EM2 are your two possible ending moods.

Above, the valley on the left represents how stressed you are before starting one of two possible relaxing activities. The peak in the middle represents how stressed you'll be when attempting to get the activity underway, and the valley on the right represents how stressed you'll be once you're done.

For the sake of simplification, let's say that stress is the opposite of willpower, such that losing stress means you gain willpower, and vice versa. For many people, there's a point at which it's very hard to take on additional stress or use more willpower, such that getting started on an activity that would normally get you to ending mood 2 from an already stressed starting mood is very hard.

In this figure, both activities restore some willpower. Activity 2 restores much more willpower, but is harder to get started on. As with chemical reactions, the most (emotionally or chemically) stable end state is not always the one that will be reached if the "easiest" activity or reaction that one can get started on is undertaken.

In chemistry, if you want to make end material 2 instead of end material 1, you have to make sure that you have some way of getting over the big peak at transition state 2—such as by making sure the temperature is high enough. In real life, it's also good to have a plan for getting over the big peak at the point of topmost stress. Spending time or attention figuring what your ending mood 2-producing activities are may also be worthwhile.

Some leisure activities, like browsing the front page of reddit, are ending mood 1-producing activities; they're easy to start, but not very rewarding. Examples of what qualifies as an ending mood 2-producing activity vary between people—but reading books, writing, hiking, meditating, or making games or art qualify as ending mood 2-producing activities for some.

At a minimum, making sure that you end up in a high willpower, low stress ending mood requires paying attention to your ability to handle stress and conserve willpower. Sometimes this implies that taking a break before you really need to means that you'll get more out of your break. Sometimes it means that you should monitor how many spoons and forks you have. In general, though, preferring ending mood 2-producing activities over ending mood 1-producing activities will give you the best results in the long run.

The best-case scenario is that you find a way to automatically turn impulses to do ending mood 1-producing activities into impulses to do ending mood 2-producing activities, such as with the trigger action plan [open Reddit -> move hands into position to do a 5-minute meditation].