Why should anyone trade when drunk?
Coz its fun

you never know where being drunk will get you. Its like gambling and trading simulteneously. You never know what crap you will buy and how it will end. Some people drink to trade, because they are afraid to make decision while being sober. So being drunk while trading can be a valuable experience.
I will have to disagree, it is true that some people enjoy themselves more when they have a few drinks, and while there is nothing wrong with that, there is a place and time for this kind of behavior, and drinking while trading the markets is not the time or place to do so.
Trading is not supposed to be fun, it is just like any other job, if you are lucky you will be one of the few people which loves their job and you will like to trade, but if you do not enjoy to trade there is no reason to try to make it fun by drinking, trading is so challenging already that traders cannot obtain profits even while sober, and I do not see any reason to make things even more difficult for ourselves by drinking alcohol.