Soccer flops?

A quick question for the Soccer elite.  What is up with the guys acting like they are paralyzed after every fall?  Is it to draw harsher penalties or is there some strategy to it?  Can a flop be called by the referee?  Is it a cultural thing and if so what countries think it is bush and which countries work it like they are D. Wade and P. Pierce.

Considering the harshness and passion of some of these poorer countries I'm a little surprised culturally they would allow that kind of behavior from their athletes.