Investing for long term makes full sense. Though most Wall Street people would disagree, two guys from Omaha agree and did well so far.

Statistics since 1926 showed that the longer holding period, the lower probability one will lose money in S&P 500:

Holding Period | Annual Return | Times of -ve Return
---------------------------------------------------------
1-year | 10.5% | 26.2%
5-year | 9.8% | 14.5%
10-year | 10.4% | 6.4%

Source:
http://allfinancialmatters.com/2013/01/31/sp-500-1-year-rolling-total-r…
http://allfinancialmatters.com/2013/08/02/sp-500-5-and-10-calendar-year…

Buy during a bad year and hold for 3-5 years, chances of getting a decent return is almost guaranteed.

So, why waste energy and time chasing daily or monthly or quarterly returns (with probability of losing at maybe 50% or more), year after year, when you can make money in your sleep, year after year?