Drunken patient: I guess it depends how drunk they are. But if the person was pretty intoxicated (i.e. slurring speech, having trouble walking)there's no way I would treat him/her. First, I think that poses a risk to you. I mean, what if the person makes a sudden random movement and you stick yourself with a needle. Not to mention the risk to the patient!! Second, I think there might be some liability/legal risk with that.
If the patient really was in a lot of pain with a tooth or something, I would tell them to go grab a drink of water and eat a bagel (if they can chew) and come back in an hour. But again, it all depends how drunk they are.
But seriously, if some hammered person came into my office I would be like: "Whaazzup dude!!!" and I would go to my office, pull out the bottle of Jack Daniels and start taking shots with him/her. 😛