According to a recent study at University of Missouri:
"It turns out that we still know we are making mistakes when intoxicated. We just don't care."
The whole article is worth a read:
Some more info about what alcohol does from lifehacker. This line in particular caught my attention:
"Substances such as cocaine and LSD work like pharmacological scalpels, altering the functioning of only one or a handful of brain circuits. Alcohol is more like a pharmacological hand grenade. It affects practically everything around it."
I don't know if all this makes me want to drink less or drink more.