Why are some jokes so funny?

Doctor, Doctor why are some jokes so painfully funny -It must be the punchline

What do these jokes and a ghost have in common?

Boo man! Boo!

What do you get when you have barbie dolls standing in a line?

A barbie queue (BBQ)! Also, I made a quick sketch on my iPad. I found the genesis to this joke as a text note in my Evernote this morning, after what seemed like a night of free flow beers. Feel free to downvote me to oblivion.

Punchline Jokes More Punchline Jokes

What's the joke where the punchline is 'thats the punch-line'?

This is no joke.

What does a Redditor do at prom?

He looks for the punchline