Expected Value, Dichotomy of Control, Good Things are Easy to Get, Life is Short. I use these thinking tools daily and they may help you as well.
Expected Value
Plans are worthless, but planning is essential – Dwight D. Eisenhower
Expected value is the sum of all possible outcomes' values weighted by the probability of the outcome. Say you play a game involving a fair coin flip. If you win, you get $10, if you lose, you lose $12. In other words, the value of heads, V(heads), is 10, and the value of tails, V(tails), is -12. Since it's a fair coin, P(heads) and P(tails) are both 0.5.
EV (heads) = P(heads) * V(heads) = 0.5 * 10 = 5
EV (tails) = P(tails) * V(tails) = 0.5 * -12 = -6
EV (total) = EV(heads) + EV(tails) = -1A negative EV means the game is not worth playing. But real life is a lot more complicated and complete information is usually impossible: what's the EV of performing a database migration? How about the EV of building a new testing framework instead?
As a thinking tool, the point of EV is not to come up with a perfect formula in order to crunch the numbers (though in the rare case where you have all the data, such as casino games, you should do that). Rather, the value is in the planning itself. By attempting to address the EV question, you are forced to think about the potential outcomes, the probability of those outcomes, and their payoffs (positive and negative). This can often lead you to discover outcomes that you had not considered. Or perhaps there is an externality that should be internalized.
Don't Overdo It: EV models are similar to other tools like Discounted Cash Flows and SWOT analyses. These are imperfect models that can lead to overconfidence. Remember that these models encode all of the biases of the people who build them. Try to question the validity of the assumptions, especially your own.
Dichotomy of Control
God, grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference. – Serenity Prayer
Traffic, delayed flights, or that time you embarrassed yourself in front of everyone at the holiday party (or anything else in the past for that matter). These are all beyond your control and getting frustrated does not change anything except your blood pressure. Rather, you should focus your energy on the things you can control.
In the strict version of the Dichotomy of Control, you only have control over a few things such as desires and attitudes. Theoretically, what you have for lunch, or whether you have lunch at all is beyond your control. But let's remember that this idea was popularized by the Stoics during a period of constant war, disease, and social upheaval by modern standards. Since we are fortunate enough to live in the Long Peace, I think we can practically expand the circle of our control to include what we have for lunch.
In Guide to the Good Life, William Irvine suggests revising the Dichotomy of Control into the Trichotomy of Control: things you cannot control, things you can control, and things you can partially control. Regardless of which version you use, the core idea is to identify things beyond your control and stop worrying or stressing about them.
Don't Overdo It: If you mis-identify too many things as beyond your control (when they are actually partially under your control), then you run the risk of fatalism.
Good Things are Easy to Get
From the Four Cures. The ancient Greeks believed that the good essential things like food, water, and shelter are easy to obtain.
If you're reading this, you probably have more than food, water, and shelter. Much more: air conditioning, refrigeration, microwaves, dishwashers, vacuum cleaners, automobiles. Penicillin, sanitation, smallpox vaccine, toilet paper. Fresh fruits, vegetables, meats, fish, butter, coffee, tea, eggs available from the local grocer. A device in your pocket that lets you access humanity's collective knowledge and entertainment of every flavor in seconds. Did I mention that it can also communicate with loved ones across the planet instantly and for free? Our ancestors from just three generations ago could not have imagined or believed this. The typical person living in the US today eats better than the median monarch from two hundred years ago.
Maybe someone made a rude comment about your work. Maybe there is red tape and pointless bureaucracy at work. These kinds of things can cause us to focus on the dead leaves on a tree and miss the forest. The fact is we are in the top 1% most fortunate people to have ever lived.
So slow down, take your time and enjoy that cup of coffee. By appreciating the Good Things and wanting the things we already have, we can face inevitable problems with more equanimity and effectiveness.
Don't Overdo It: don't become impervious to warnings/critical feedback. Don't use this as an excuse to ignore real problems.
Life is Short
Today will never happen again and it's one day closer to the end. Thinking about death sounds morbid, but it's one of the most effective ways to not misspend time, the most precious resource of all.
We have two lives, and the second begins when we realize we only have one. – Confucius (one of the few good ideas Confucius had)
Did your actions today get you closer to your goal? If not, what adjustments do you need to make? Do you know what the goal is? How will you review your life upon your death bed? These are personal answers, and examining them can lead to a greater sense of purpose, which can improve both kinds of happiness.
Maybe you're young and invincible. Try this: create a spreadsheet where each cell is one week. Then fill in the most significant events of your life. You will find that the spreadsheet is frighteningly short. Some say near-death experiences make you appreciate life. Maybe there's a way to learn that without the near-death experience.