Drinking

I'm wondering, why do people drink like fish? I mean some people can drink a whole 1.75L bottle in one sitting and be messed up...falling down drunk and not even care about it! Falling out in public, not able to pronounce words correctly, unable to walk upright, black-outs... WHY? Ok, I have had my share of drunken nights, but not to that extent(2-3 times a week maybe more) and especially not out in public, well except for those times in Japan... but that is ok there...lol

Who gets up and starts drinking in the morning just because there is liquor there? 11am!!?!?? WTF?! Then gets pissed at you because you point out the time and the obvious problem. Every now and then... a blue moon, but not often.

Are there emotional issues they are dealing with? Self-esteem issues? Or can you possibly like liquor that much? How do you know when you are an alcoholic? How do you know when it is affecting your health? How can you stop or is the most important thing is wanting to?