In the Federalist Papers, it is argued that the wills of the factions are kept in check by those of other factions. In other words, competing interests will stop any one group from getting too much power. Examples of this are seen throughout society (the most obvious being the conflicting interests of the Democratic and Republican parties). For every group with a strong opinion and set agenda, there is another group to oppose it. Therefore, somewhat ironically, it is only by the abundance of factions can each individual faction be controlled and stopped from obtaining too much power.
In our entire society, competition is a driving force. Competition between the branches of government has been persistent throughout history as attempts for one branch to gain significantly more power have been thwarted by the other branches (FDR's court packing scheme, Clinton's line-item veto, etc.)
Concerning the economy, Smith argues that competition is one of the crucial elements to safeguarding against uncontrolled self-interest. The article , "The Wonderful World of Adam Smith," states, "A man who permits his self-interest to run away with him will find that competitors have slipped in to take his trade away..." It seems that Smith's "forces" which "bring [output or prices] back [from their socially ordained levels]" are largely dependent on the factor of competition.
Competition in our economy is highly prevalent, whether it be Orbit gum versus Trident, or Macs versus PCs. Competition in the economy seems to be necessary for economic growth, not only by acting as a safeguard to unregulated self-interest, but also by forcing continuous improvement of products, regulating quantity of goods produced, and regulating incomes.
For all of these reasons: governmental checks on powers, safeguards against factions, protection against too much self-interest in the economy, I believe competition to be a crucial aspect of society.