The problem with var is not the fact it exists.
It's when it takes minutes to decide (disallow) a goal for the silliest of distances that it fails.
It's meant to back the referee up and pick up on things he has missed. The minute you stop a game for 2-5 minutes to determine a decision you are breaking the game completely.
It's the death of football as we know it. As the villa goal proves the other week when he put it in the top corner, or these armpit offsides, it's removing the flow of the game to the extent it's dying.