A guy walks into a bar and says to the bartender

I want you to give me 12-year scotch, and don't try to fool me because I can tell the difference." 

The bartender is skeptical and decides to try to trick the man with 5-year scotch. The man takes a sip, scowls and says, "Bartender, this crap is 5-year scotch. I told you I want 12-year scotch." 

The bartender tries once more with 8-year scotch. The man takes a sip, grimaces and says, "Bartender, I don't want 8-year scotch like this filth. Give me 12-year scotch!" 

Impressed, the bartender gets the 12-year scotch, the man takes a sip and sighs, "Ah, now that's the real thing." 

A disgusting, grimy, stinking drunk has been watching all this with great interest. He stumbles over and sets a glass down in front of the man and says, "Hey, I think that's really far out what you can do. Try this one." 

The man takes a sip and immediately spits out the liquid and cries, "Yechhh! This stuff tastes like piss!" 

The drunk's eyes light up and he says, "Yeah, now how old am I?"