drinking makes you look stupid and as if you don't have control over yourself, which in most cases you don't.
it can cause cancer, destruction of the liver (cirrhosis), and in extreme cases, brain damage. my grandfather died from esophageal cancer because he drank merely 2-3 drinks each week (he did it for years, though). drinking is not worth risking your life over. however, a little wine every now and then can't do any harm.