And unless you're incredibly stupid with it 5 glasses of alcohol will never kill you either. But yes you can die from drinking too much water, basically you become over hydrated and drown on your own lungs. Awesome. At least with alcohol there is generally for most people a time when they sit there and think "hey I best not have anymore" if they are smart they'll listen to themselves when that point occurs, if they're stupid they'll carry on drinking and pass out, if they're stupid and unlucky they might end up in hospital.

Edit: and before you say it, drinking alcohol is a ton more sociable than drinking water, drinking alcohol is no fun if done alone so therefore people congregate together to get wrecked and yes, it is in fact more sociable for all the reasons you, Remon posted as a bad thing, the lack of inhibitions (consider the pro's the phrase dutch courage for example a shy person can approach someone after a couple of drinks and tell them what they believe/feel ect) the stupid things we do when drunk (the pro here being it's creating those stories what stick with you for life and when you get married provide the best man with the things he will undoubtedbly say in his speech), the saying things you shouldn't (see the inihibition thing, some people who are subjugated by boisterous friends will actually open up when drunk and let them know it's not something they're happy with) there are as many pro's to alcohol as there are con's and no one sympathises more than a drinker sympathises to a hung over person.