An interviewer once asked Dr. Phil if it bothered him that so many critics accused him of oversimplification. He responded that it didn’t bother him at all. He even volunteered that one fellow had recently accused him of saying things that were really nothing more than common sense — to which Dr. Phil responded, “Golly, that’s great. Do you mind if I use it as a testimonial?”

I have to give Dr. Phil a 10 on that one. And the nice thing about it is that it was true. The greatest teachers have a knack for demystifying complex issues by applying common sense to them. It goes without saying that Paul Ryan and his congressional allies who have been trying so hard to explain the problems involved in replacing Obamacare are most decidedly not good teachers, because most of the public has no idea what they’re talking about.

So, just what is common sense? A good technical definition of common sense is “sound judgment that is not based on specialized knowledge.” In other words, you don’t need to be a Ph.D. to exercise common sense. It’s a trait you develop through purposeful awareness and habit. I should also add that in order to be aware and to develop habits requires self-discipline, the self-discipline to do the right thing rather than doing what makes you feel good in the present moment.

Common sense is closely aligned with wisdom, whereas an academic understanding of specific areas of life is aligned with knowledge. In simpler terms, what common sense boils down to is a sound understanding of how life works. This requires that a person learn through his experiences and not delude himself about the causes that lead to his consequences.

Having said this, I believe that most people have a reasonably good understanding of the right thing to do in any given situation. In other words, they know the difference between responsible and irresponsible actions. The problem, however, is that too many of these same people — at the moment of truth — have a habit of ignoring their intellect and instead acting on emotion, which signifies a lack of self-discipline.

I can’t stress it enough: All the common sense in the world is useless if one doesn’t have the self-discipline to apply it. From whence comes the old adage “You have to walk the talk.”

Children — especially teenagers — have a tendency to act on emotion more often than most adults. But teenagers have an excuse: They’re short on experience. With each passing year, an adult has more and more experience under his belt, and thus less and less justification for acting on impulse.

In fact, a good definition of maturity is the willingness to forego instant gratification. At some point in time, an adult — to be successful — must learn through his experiences or be prepared to pay a heavy price throughout life. Thus, it all gets down to experience, the wisdom one takes away from his experiences, and having the self-discipline to apply that wisdom to other situations (association).

When I watch the daily news, it amazes me how many sad, even tragic, stories are a result of people’s common sense taking a leave of absence when they most need it. I always try to focus on the common-sense angle of these stories and mentally file away the lessons I learn from them.

My hope is that by doing so I will be able to avoid similar lack-of-common-sense mistakes in my own life. As a result, I often find myself thinking of these mistakes at critical moments. Learning is one of the most wonderful aspects of life, but it doesn’t count for much if you don’t apply what you’ve learned to real-life situations. Many people who appear to lack common sense simply fail to apply what they already know.

It’s important to understand that common sense is not something you inherit at birth. Like most traits, anyone can acquire common sense and improve upon it every day of his life.

One of the reasons I became so enamored with Albert Einstein’s quote “Nothing happens until something moves” is because it’s the epitome of common sense. Tens of millions of people seem to be waiting around for something good to happen in their lives, while expending enormous amounts of energy complaining about their “bad luck.” The term most commonly associated with this is victimization, a mind-set that has become an epidemic over the past 50 years.

As I have written about so often, most people tend to miss the most obvious things when it comes to success in any area of life. While in search of the magic formula for success, they mistakenly overlook the importance of something as simple as common sense. I suggest you forget the magic formula and simply focus on applying common sense in all situations.

Demonstrating common sense on a consistent basis doesn’t guarantee success, but a lack of it can come pretty close to guaranteeing failure. Above all, remember that consistently deferring to your common sense before making decisions is nothing more than a habit, and, fortunately, all habits can be learned by anyone who brings willingness to the game of life and couples it with consistent self-discipline.