Pleasure is a wonderful thing but what if there was a button that was wired into the pleasure center of our brain that we could push that would give us pleasure.  What would happen if we kept pushing that button? 

What would happen to our relationships with other people?  Would we bother socializing or caring for others or working or learning or striving to make the world a better place when it's so much more pleasurable to push a button instead?

There are analogous things in life to that button such as drugs and pornography.  They all are destructive.