Phrases or quotations that don't mean what they literally say.

Person at work needs to squeeze by me.
They say "Excuse me"
I answer "You're excused"

Quote: rxwine

Well, I'd look like a genius if I knew which one of the IPOs was going to blow up years later and which ones were going to go kaput.

Twain lost a tonne of money on the Paige Typesetting machine, which promised much, but delivered very little. He had to shut down his big house and go back as a touring author in his later years.

"Let us live so that when we come to die even the undertaker will be sorry"

Quote: AZDuffman

History is filled with missed things that later became obvious. USA companies invented the VCR but wondered why people would tape shows? GM and Ford both figured minivan sales would not work because van buyers thought it was too small. How many others?

In the late 80's Bill Gates couldn't see the
value of the internet, so he let others
develop software for that. He said in 1997
that if you told him in 1988 that McDonalds
was going to have their internet address
of their commercials, he would have said
you were nuts. I forgive Twain.

The "hoi polloi" 1837. Almost always used with a preceding "the" even though "hoi" means "the" in Greek.

Despite the word "polloi" being related to the commonly used prefix "poly-", the phrase "hoi polloi" is frequently misused to mean the opposite of it's true meaning.

Quote: Pacomartin

The "hoi polloi" 1837.

I always took it as term meant to be derogatory
against unwashed masses.

Phrases that literally mean what they say can be very funny. Groucho Marx was a master at this:

"Outside of a dog, a book is a man's best friend. Inside of a dog it's too dark to read."

"I've had a wonderful time. but this wasn't it."

And his famous paradoxical: "I would never join a club that would have me as a member."

In the same vein he said:

I've had a perfectly wonderful evening. But this wasn't it.

and

A child of five would understand this. Send someone to fetch a child of five.

The gods are on the side of the stronger.
The gods help them that help themselves.

Good examples of skepticism even before there was monotheism.