Can you tell my a joke?

I heard this one recently:

A man walks up to a bar near closing time and asks the bartender for 20-year old bourbon. The bartender wants to close, and thinks, 'I'll just give this guy whatever so he'll leave' and pours him a glass of 5-year old bourbon. The man takes a sip and spits it out. He says, "I know my drinks. That was 5 year old. I want 20. Can you please give me 20 year old bourbon?"

The bartender, still wanting to get out, thinks the guy is full of crap and pours him 10-year old bourbon. The man sips it, spits it out. He says, "I told you, I know my drinks. Please give me 20-year old bourbon."

The bartender now is annoyed but curious, and pours him 15-year old, and the same thing happens. "Bartender, I know you have 20-year old bourbon. Please give me what I am asking for?"

The bartender is now impressed and pours the 20-year old bourbon. The man sips it and sighs happily. "Thank you sir!" and he pays his tab.

Another man who was watching this unfold nearby walks up to him with a glass of amber liquid and says, "I'm impressed that you know your drinks so well! Please have a drink on me."

The bourbon man takes a sip and spits it out right away. "This tastes like piss!" he exclaims.

The second man smiles. "You're correct, it is piss! Now tell me how old am I?"

Guy walks into a doctors office with a frog on his head
Doctor says what's wrong with you and the frog replies,
It started with a bump on my ass...