Fast and/or difficult tasks which engage both hemispheres of the brain require rapid, efficient communication between the left and right brain.
Research indicates that southpaws demonstrate significantly better abilities at such tasks than right-handed people who tend to be more efficient at tasks necessitating use of only one cerebral hemisphere. Apparently the brains of lefties are wired differently and more symmetrical than those of right-handers.
So what are some of the tasks lefties are better at than the great majority of the population? Playing fast computer games, driving in heavy traffic and piloting a jet fighter are a few of them.
Also lefties cope better with the ravaging affects which age has on the brain.