The little dips are all the post-WWII recessions. The big dip at the bottom, the one that drags on for years and years and is so very, very deep is the 2008 Great Recession caused by Wall Street greed and three decades of right wing propaganda calling to "shrink government" and "deregulate, deregulate, deregulate". Mission accomplished. The lunatics took charge of the asylum and you got the Great Recession.
Sadly, the lunatics still haven't given back the keys. The same right wing nuts who help prepare the groundwork for this financial disaster are still selling the poisonous intellectual fare of "freshwater economics". It still has the upper hand when you look at the vicious austerity programs of the Republican dominated state legislatures and when you survey the outrageous Ryan "budget" which is more a political dictat than a budget plan which could be followed.