Catch 22

"They're trying to kill me," Yossarian told him calmly.
"No one's trying to kill you," Clevinger cried.
"Then why are they shooting at me?" Yossarian asked.
"They're shooting at everyone," Clevinger answered. "They're trying to kill everyone."
"And what difference does that make?"
Yossarian explains to his friend Clevinger why he is not crazy for thinking people are trying to kill him, Chapter 2: Clevinger.

There was only one catch and that was Catch-22, which specified that a concern for one's own safety in the face of dangers that were real and immediate was the process of a rational mind. Orr was crazy and could be grounded. All he had to do was ask; and as soon as he did, he would no longer be crazy and would have to fly more missions. Orr would be crazy to fly more missions and sane if he didn't, but if he was sane he had to fly them. If he flew them he was crazy and didn't have to; but if he didn't want to he was sane and had to. Yossarian was moved very deeply by the absolute simplicity of this clause of Catch-22 and let out a respectful whistle.
"That's some catch, that catch-22," he observed.
"It's the best there is," Doc Daneeka agreed.
Doc Daneeka explains why he cannot ground Yossarian or Orr due to insanity, Chapter 5: Chief White Halfoat.

"Catch-22...says you've always got to do what your commanding officer tells you to."
"But Twenty-seventh Air Force says I can go home with forty missions."
"But they don't say you have to go home. And regulations do say you have to obey every order. That's the catch. Even if the colonel were disobeying a Twenty-seventh Air Force order by making you fly more missions, you'd still have to fly them, or you'd be guilty of disobeying an order of his. And then the Twenty-seventh Air Force Headquarters would really jump on you."
Doc Daneeka reveals another clause of Catch-22 to Yossarian, Chapter 6: Hungry Joe.

Some men are born mediocre, some men achieve mediocrity, and some men have mediocrity thrust upon them.
Of Major Major, with whom it had been all three. Chapter 9: Major Major Major Major.

With a little ingenuity and vision, he had made it all but impossible for anyone in the squadron to talk to him, which was just fine with everyone, he noticed, since no one wanted to talk to him anyway.
Of Major Major. Chapter 9: Major Major Major Major.

Major Major never sees anyone in his office while he's in his office.
Sergeant Towser to Appleby. Chapter 10: Wintergreen.

Open your eyes, Clevinger. It doesn't make a damned bit of difference who wins the war to someone who's dead.
Yossarian, Chapter 12: Bologna.

It doesn't make sense. It isn't even good grammar. What the hell does it mean to disappear somebody?
Yossarian is told by Nurse Duckett that officials are planing to "disappear" Dunbar, Chapter 34: Thanksgiving.

Joseph Heller