Excerpted from OFF BALANCE: Getting Beyond the Work-Life Balance Myth to Personal and Professional Satisfaction by Matthew Kelly. Published by arrangement with Hudson Street Press, a member of PenguinGroup (USA), Inc. Copyright (c) Beacon Publishing, 2011.

By Matthew Kelly

It is a common and childish mistake to believe that satisfaction is allabout getting what we want. In truth, we have all gotten what we want onmany occasions and not been satisfied. The very basis of satisfaction isa value structure, or a set of priorities, around which to live yourlife.

Can you have it all? Any reasonable person knows the answer tothis question is no. It is one of the earliest lessons we learn inchildhood, and yet, most of us as adults can be quite childish at times.

Excellence in any field requires that we miss out on other things.

The reason you cannot have it all is not because you are ill equippedfor life, or lack talent, or because you don't have enough money. It issimply because one of the governing principles of the universe dictatesthat there are an infinite number of possibilities for any day, year, orlife -- and every day, year, or life is finite. And so, part of growingto maturity, part of growing up, requires that we recognize and acceptthat we cannot have it all.

Most of us recognize that we cannot have it all, but often wesubconsciously fall back into moments of non-acceptance. We know wecan't have it all but we refuse to accept that. You can see how thiskind of pattern could lead to a great deal of frustration at the veryleast and real insanity if taken to the extreme.

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The work-life balance discussion has failed to adequately make clearthat you cannot have it all. Just because we started talking aboutwork-life balance and encouraging it, does not mean that people can allof a sudden have everything. I cannot play tennis and golf at the sametime. The finite nature of a certain period of time requires that Ichoose to play tennis or golf this afternoon. I cannot do both at once.We have to choose between many options in deciding what to do on anygiven day or in any given hour.

The other way this idea plays out is that excellence in any fieldrequires that we miss out on other things. If you want to be the besttennis player in the world you are going to have to sacrifice a greatmany other things in order to achieve that. Hopefully you have to decidewith a clear head that the things you are giving up are less importantthan becoming the best tennis player in the world.

Success always hasand always will require sacrifice. If success were easy it would becommon. It is difficult and that is why it is rare. More people have thetalent than you would think. Few are willing to make the sacrificesnecessary. This is an easy example because it is far from us. But let usbring it closer. Make it real and personal.

To be the best marketingexecutive in the world requires sacrifice, to be the best HR contact,the best salesperson, the best manager, the best employee, the bestaccount manager... All require sacrifice, and I am not sure that thework-life balance discussion of the last 20 years has adequately pointedout that excellence in any field requires sacrifice.

And perhaps you have no desire to be the best at what you do. Perhapswork is just work, something you have to do. In that state of mind youwill find it very difficult to experience professional satisfaction, andthat will be sure to have an impact on your personal satisfaction as thetwo are intimately linked. Nonetheless, lets bring the example one stepcloser. Perhaps uncomfortably close.

A mother who works cannot expect to be able to do everything for herchildren that a mother who stays at home does. That does not necessarilymean she is a bad mother or that her children are worse off. But thesimple fact remains that her work will require a certain amount of time,energy, and attention -- all of which cannot be given to both work andher children. She may have plenty of time, energy, and attention for herchildren outside of work. Only she can decide that. But the mother whodoes not work will by simple math have more time, energy, and attentionto give her children. The reality is that a working mother cannot expectto do everything a stay at home mother does. There are trade offs thatneed to be made.

In a way the work-life balance discussion has made us feel that we couldhave it all, and we cannot. Most people don't want to hear this andcertainly our culture tell us incessantly that we can have it all, butthe truth is you can't. You cannot be in two places at one time, youcannot have it all, and so we must choose.

This commentary comes from an independent investor or market observer as part of TheStreet guest contributor program. The views expressed are those of the author and do not necessarily represent the views of TheStreet or its management.