A friend will watch the football game with you.
A best friend will watch the football game with you so they can serve as an eyewitness to your whereabouts for his murder trial.

A friend will help you cheat on your girlfriend.
A best friend will help you cheat on his girlfriend.

A friend will help bail you out of jail.
A best friend would be right there in jail with ya. After all, getting the weed was his idea.

A friend will pop back a few beers with you.
A best friend will pop a few back pimples for you.

A friend will let you crash at his place for the night.
A best friend will let you crash his Suburban for the insurance money.

A friend will pick up a check at dinner.
A best friend will pick you up a chick for after dinner.

A friend will set you up on a blind date.
A best friend would just save you the trouble and poke your eyes out with dinner forks ahead of time.

A friend will invite you over to his house for a party.
A best friend will invite you over to his house for an orgy.

A friend will help you plant a tree at a forest.
A best friend will help you plant some evidence at a crime scene.

A friend will take a bullet for you.
A best friend will take a bullet out of you…with his teeth.

A friend will give you one of his kidneys.
A best friend will give you one of his first-born kids.

A friend will take you out for lunch.
A best friend will “take someone out” for you.