How many Computer problems are solvable with a simple Restart? probably most.
How many Website problems are solvable with Clearing the Cache? not most, but a lot.

Especially in complex systems (*cough* Drupal *cough*..) one could go insane trying to figure out
why those simple changes ("yes I checked the file path!!!") that you are trying to do ("yes it's the right server!!!"),
for some odd reason ("yes the permissions are set!!!") do not happen.

Suddenly, you a moment of enlightenment comes, in which your eyes go wide open and your mind is screaming CACHE!
(unlike the average broker where it screams CASH).

May it be Drupal, Wordpress, some PHP Framework or whatever it is that you fancy, never forget the bullet proof solution - Clear Cache.