If you are serious about playing Pac-Man...

... then you might benefit from reading GameInternals' analysis of strategy and tactics.

Each of the ghosts is programmed with an individual “personality”, a different algorithm it uses to determine its method of moving through the maze. Understanding how each ghost behaves is extremely important to be able to effectively avoid them...

The key to understanding ghost behavior is the concept of a target tile. The large majority of the time, each ghost has a specific tile that it is trying to reach, and its behavior revolves around trying to get to that tile from its current one. All of the ghosts use identical methods to travel towards their targets, but the different ghost personalities come about due to the individual way each ghost has of selecting its target tile...

One important implication of Pinky’s targeting method is that Pac-Man can often win a game of “chicken” with him. Since his target tile is set four tiles in front of Pac-Man, if Pac-Man heads directly towards him, Pinky’s target tile will actually be behind himself once they are less than four tiles apart. This will cause Pinky to choose to take any available turn-off in order to loop back around to his target. Because of this, it is a common strategy to momentarily “fake” back towards Pinky if he starts following closely. This will often send him off in an entirely different direction.

Lots of stuff like that at the link.