Power.  For some over the eons of history, power has been a motivating force.    

Even in the modern age, there are still some who employ this age-old tactic to put the world on notice.  None is more recent than what is happening in the Eastern European region.  

Troops amassing on borders.  Military presence growing, and global leaders engaged in 'diplomacy'.  Could it escalate? or is this all posturing and flexing?  In modern times, engaging in full-scale war could have far more devastating consequences other than the obvious potential (and possibly inevitable) loss of life.  

If anything, recent history has shown us that for the most part, this is all about putting the rest of the world on notice. Not too dissimilar really to the school bully acting up thinking they need to remind everyone else they still exist.