What are the benefits of meditation? [Spirituality & Religion]

I have been recently made aware that perhaps a majority of the population is actually [i]not able to terminate or change their train of thought effortlessly and at will[/i]. Which is basically the psychical hygiene equivalent of what wiping your ass with your hands every time you shit and never, ever washing them would be to physical hygiene. Non-half-assed meditation will help clean up the mountain of crusty old shit that probably constitutes the greater part of your mind.