Know your limits

A guy has a son that was born deformed, with no torso, arms or legs.
He still loves his son and treats him as normally as he can. On the boy’s 18th birthday, he takes his son to a pub to celebrate. He places his son on the bar and tells the barkeep: “TWO PINTS! ONE FOR ME AND ONE FOR MY SON!”

He tells his boy “Happy birthday” and holds the glass up to his boy’s mouth so he can have a drink…. BAM! a torso pops out from the son’s head! “OH, thank the heavens, my son has a BODY!” says dad.

Then he quickly tells the barkeep to bring another pint… He holds it up to his son’s lips, and pours. BAM! legs pop out!
“HALLELUJAH!” yells dad.

“GIMME ANOTHER PINT!” he shouts to the barkeep.

BAM! this time ARMS pop out, and the son appears to be perfectly normal!

Dad starts crying and hugs his son. Then he tells the barkeep, “barkeep, a pint, please for me and my son to celebrate this miraculous event”

The dad and son down the pints, and suddenly….
BAM! the son explodes, and nothing is left :-O

The barkeep walks up to the dad, and says:

“The moral of this story is that people should …

… quit while they’re a head.