I was thinking about things that make people happy - money, food, good fortune (those are some of the superficial ones) - and then I thought about the things that would make people unhappy - using these same dumb examples: lack of money, lack of food, and bad fortune.
And a lot of times, not having things is why people will become sad. People will dwell on the good things that they don't have - like a new car, or the best clothes, or a better TV - and not on the good things that they do have.
But judging on today's standards, and especially in this affluent country, it may seem like you always have the short end of the stick. But instead, I propose an alternative method.
Think the opposite: think about the bad things that you don't have.
It sounds pretty stupid at first.
But when you think about it, the list can get pretty long.
you aren't dying from malnutrition,
you aren't homeless,
you aren't plagued by severe medical problems that threaten your everyday life,
you aren't wondering when you will get your next meal,
you aren't living in a war zone,
you aren't wondering if the safety of you and your family is in danger,
you aren't worrying about half of the things that more than 80% of the world population worries about everyday, like food, the weather, clothes, sickness, housing, and violence.
You are all clever people - try pulling a Polonious. As you know in Hamlet, Polonious (father of Ophelia, Hamlet's lover) conjures up a plan to learn about the things his son Laertes is doing in France. So he tells Reynaldo to ask around start spreading rumors about Laertes, and depending on how they react, that would tell him what Laertes is doing (i.e. "Hey, did you see Laertes beat up that idle mob?" "No way! Laertes would never do that! He's at the library studying!" So we find out indirectly that he is a studious and good-doing person, by asking the opposite). Clever Polonious is at it again!
It's just like with happiness - instead of directly evaluating your life, trying doing it indirectly, by thinking of the opposite of what you are actually trying to find. And you may find that it works better than you planned. Although for Polonious, life takes a sharp turn for the worse when he is killed in Act 3. Hopefully you won't be "slain" in Act 3.