A 12-year-old Scotch

A man walks into a bar and orders a 12-year-old scotch. The bartender, believing that the customer will not be able to tell the difference, pours him a shot of the cheap 3-year-old house scotch that has been poured into an empty bottle of the good stuff.
The man takes a sip and spits the scotch out on the bar and screams at the bartender. "This is the cheapest 3-year-old scotch you can buy. I'm not paying for it. Now, give me a good 12-year-old scotch."
The bartender, now feeling a bit of a challenge, pours him a scotch of much better quality, 6-year-old scotch. The man takes a sip and spits it out on the bar. "This is only 6-year-old scotch. I won't pay for this, and I insist on, a good, 12-year-old scotch." The bartender finally relents and serves the man his best quality, 12-year-old scotch.
An old drunk from the end of the bar, who has witnessed the entire episode, walks down to the finicky scotch drinker and sets a glass down in front of him and asks, "What do you think of this?"
The scotch expert takes a sip, and in disgust, violently spits out the liquid yelling "Why, this tastes like piss,"
The old drunk replies, "That's right, now tell me how old I am."