Stories of strategic games:

In  this part we  will  give  you  some practical motivation,  which will  be much  closer to your personal concerns. This will help you  understanct the subject matter. All of us play games of strategy consciously or unconsciously all  the times with our parents, employees, friends, enemies  and even with professors.  

Example

Suppose  you  are  enrolled  in  a  course, which is graded not absolutely  but relatively. No matter  how  well you  do  in absolute terms, only  40%  of  the students will  get As' and  only 40% will  get  BS'.  Therefore,  you must work hard not just  in absolute terms but relative to how hard your classmates work. Otherwise all of you can have a tacit collusion that none of you will work hard so that you can get a good grade without working very hard. 

But as examinations get nearer the temptation of working hard to get an edge over  your classmates  grow.  You  start working very hard. All of your classmates think along the same line and all of them start working hard. 

Every student in the above example had  two strategies, either work hard or do not work hard. Their grades are a result of the interaction of the strategies taken by each of them.