We are all human. 

What this means is that for some odd and unexplained  reason no mater which negotiation styles or negotiating techniques we  are using, we all seem to like things that come in threes.  In our world it seems as though all good things come in groups of  three. Think about it, your childhood was filled with three bears, three  kings, three little pigs, etc. 

It turns out that for negotiators,  things that come in groups of three can be rewarding as well.