Ah, great stuff for a new guy looking for explanations.  Between highhorse and rcjets63 I have my explanation of why we takeoff into a headwind.  It very logically reduces the take-off roll and the amount of runway needed.  It is not that you can't or you will lose control on a downwind, but a longer roll, perhaps substantially longer, will be required to get to the proper airspeed for take-off. 

While some of this stuff can stray off on tangents it is very useful to new guys (this one in particular) who are not full scale pilots and are really looking for explantions of the dynamics of flight to become a better pilot.  And if you don't know why something works or doesn't work you have a much harder time properly managing the effects.