No buffer region in the titration of strong acids or bases? So recently I have conducted a acid-base titration experiment. I encountered that there is no buffer region in strong acid-strong base reaction. However, when take a weak acid or base buffer region appears. 
WHY THIS IS LIKE THAT? What I mean is there any rational explanation for this?
Strong acids and strong bases essentially completely dissociate. So if you're adding the strong base to the strong acid, the solution stays very acidic, then neutralizes, then goes basic with just a small amount of the strong base. 

With a weak-acid at the pK value you have as much $\ce{H+}$ as $\ce{A-}$. Thus a small amount of strong base or strong acid won't change the pH value much. That is the very notion of a "buffer solution."

So yes there is a rational chemistry explanation. :-)