Truth may be absolute or truth may be relative — changing with each person's perception.

If truth is relative, discussions about truth are as important as discussing what tastes best, Coke or Pepsi. 

For example, if your perception is that walking in front of a eighteen-wheeler big rig on the Interstate will have no effect on you, your perception is directly contrary to the truth. 

In the big scheme of things, what you think about truth does matter.  It matters because truth is absolute.

Picture of my glass of Pepsi