Hitting towards the corners makes your opponent cover the most distance, and moves them away from their central base.
You can make your opponent move the farthest possible distance by moving him along a long diagonal.
Forcing your opponent to change direction puts pressure on his footwork skills.
Hitting to the same corner is a tactic that players often neglect.
Although it might seem better to hit different corners every time, it can actually be more effective to maintain pressure first on a single corner, before eventually switching your attack to a different corner.