In a familiar scene in the world of cartoons, a character is being chased. He runs and runs, with the chaser in close pursuit. Suddenly, the character reaches a cliff. Unaware, he continues to run -- first on the cliff, then past it.

As could only happen in a cartoon, the character is able to keep running, with only the air beneath him.

After a while, he looks down. He sees that there is nothing under him. He realizes that, according to the laws of gravity, he should not be where he is -- that he does not belong there. At that moment, he falls to the ground.

Sometimes, in life, the greatest obstacle to success is not the individual's limitations. Rather, it is the feeling that he or she "should not" succeed. As long as the individual believes that success is attainable, he or she could aspire to great heights. If, however, that same individual believes that he or she "should not" succeed -- if the person "looks down" -- failure is practically assured.

Recently, a friend told me about a colleague of his. The man, a newcomer to their industry, was having great success in his sales during the summer -- even though summer is the slowest season. The man "did not know any better." Since nobody told him that he should fail, he succeeded.

In 1953, Roger Bannister ran a mile in less than four minutes (3 minutes, 59.4 seconds). In the 47 years since then, the record has only dropped by about 15 seconds. One has to wonder: Are there, perhaps, people out there who, physically, could run a 3-minute mile? Are they limited only by their belief that such a thing is not possible?

Indeed, to a great extent, our success is limited by our own expectations. This applies to almost any avenue of life -- sports, medicine, finance, and (this is our subject) the spiritual dimension of our lives as well.

When Moses sent spies into Canaan, they returned, stating: "And there we saw the nefilim, the children of giants ... And we were, in our eyes, like grasshoppers." (Numbers 13:33)

It is no surprise that their conclusion was: "We cannot conquer that nation, for they [its people] are stronger than we are." (Numbers 13:31)

If you believe that you will fail, you probably will.

When one is, in his or her own eyes, as small as a grasshopper, it is likely that he or she, like the spies, will use the word "cannot." If you believe that you are limited -- you will be. If, however, you ignore the naysayers (whether they are external or simply the voices within you); if you do not "look down"; if, rather, you place your faith in God and make the proper effort -- you can exceed all expectations.

Though humility is one of the hallmarks of our people, pessimism is not. There is nothing Jewish about feeling that you must fail, or even that you must be average. We must strive for spiritual excellence. We must strive to inject as much holiness into our lives as we possibly can.

Alei Shur, the contemporary ethical classic, states: "Every person must know that he or she has importance."

There, the Midrash (Tanna D'Vei Eliyahu, Ch. 25) is quoted: "A person must ask, 'When will my deeds reach the level of the deeds of Abraham, Isaac, and Jacob?'"

Abraham, Isaac, and Jacob? My deeds? Should we set our sights that high?

Alei Shur continues: "Whenever one does not set his sights upon perfection, it is very difficult for him to attain it. When one does set his sights upon it, however, it is easily attainable."

To underline this concept, we need only to consider some of the luminaries of our past and the obstacles they overcame: Joseph (sibling rivalry; alien environment); Moses (speech impediment); Rabbi Akiva (began Torah study at an advanced age); Onkelos, author of the Targum of the Torah (a convert); and more.

If any of them would have thought that he could not possibly excel, he would have assured his own failure. Instead, each set his sights upon perfection -- and attained it.

Do you strive for spiritual excellence? Do you set your sights as high as they could be set? Do you ask yourself: When will my deeds reach the level of the deeds of Abraham, Isaac, and Jacob? Do you seek to achieve as much as you possibly can, in the performance of all mitzvot?

Do you set high goals for yourself in both the commandments between man and God (such as Shabbat, prayer, kashrut, and Torah study) and the commandments between man and man (such as charity, helping others, and playing a leadership role in kindness projects)?

Remember: If you believe that you will fail, you probably will. If, however, you believe that, with God's help, you can succeed and even excel, you are on your way. Set your sights high -- and don't look down.

Excerpted with permission from "DON'T LOOK DOWN" -- refreshing perspectives on everyday life. By Rabbi Michael Haber. Published by ArtScroll/Mesorah Publications Ltd., Brooklyn, NY.