Are you happy? The answer to that question probably varies from day to day, doesn't it? In fact, it can vary from hour to hour and even minute to minute throughout any particular day depending upon your circumstances.

So how can you be happy most of the time? The secret to happiness is something that many people search their whole lives for. But what are they searching for?

If you ask people what makes them happy, you're bound to get a wide variety of answers. For some people, happiness is synonymous with money: the more money they have, the happier they are. This may be because they associate happiness with material possessions, such as homes, cars, or the latest smartphones.

Others find happiness in their relationships with family members and loved ones. Still others may look to their faith, jobs, or hobbies.

If you sought advice about happiness, though, who would you talk to? A spiritual guru? A psychologist? How about a famous scientist widely-known as one of the most brilliant minds of the last century?

If you had a question about quantum physics, then Albert Einstein would probably be high on your list of people to consult. But what about happiness? To the surprise of some people, Einstein also had some deep thoughts about happiness.

For example, Einstein is well-known for the following quote: "If you want to live a happy life, tie it to a goal, not to people or things." This would seem to advise against seeking happiness in possessions or relationships. Perhaps Einstein felt this way because his scientific work gave him such fulfillment.

And why wouldn't it? He was quite successful. In fact, while traveling in Japan in October 1922 to give a series of lectures, he learned that he had won the 1921 Nobel Prize in physics.

Did the award make Einstein happy? Probably! However, he didn't cancel his plans in Japan to attend the award ceremony in Stockholm.

While staying at the Imperial Hotel in Tokyo, Einstein one day found himself short on cash when he wanted to tip the bellboy. In lieu of cash, he gave the bellboy two handwritten notes, telling him they might one day be worth much more than a regular tip.

He was right! One of those handwritten notes — commonly known as the "happiness letter" — recently sold at an auction for $1.56 million!

So what advice did it contain? In full, the letter reads as follows: "A calm and modest life brings more happiness than the pursuit of success combined with constant restlessness." It sounds like Einstein was advocating against the restless, constant pursuit of happiness that characterizes so many lives today.

Should we slow down and let happiness find us? Some people do believe that the secret to happiness is being satisfied that everything you already have rather than always searching for something new. What do you think?