What are the consequences of excessive drinking?

Solution 1:

There are many effects that occur but I wouldn't classify any of them as "Fatal". The things that will happen:

Negative effects:

• Your screen goes blurry
• You can't really walk straight anymore (swimming and flying can be really tough)
• If you say something in chat "S" will occasionally become "SH" and sometimes a "...hic!" is added randomly.
• The level of NPCs is displayed as 5 levels lower (the real level still remains the same though).
• You can get a debuff "Totally Smashed" that will cause you to vomit. You are stunned during this.

Positive(?) effects:

• You can get an achievement for falling 65 yards if you're drunk during the brewfest.
• Yay let's get smashed in an MMO!

Your Drunk status will go away after some time or on-death.

Solution 2:

Drinking makes you walk and and run in staggering lines, the screen becomes blurry, your typed speech is slurred and punctuated with hiccups, your toon will puke, and the levels of hostile (confirmed), neutral (confirmed) and friendly (unconfirmed) mobs will appear lower.