Yossarian's liver

Yossarian ran right into the hospital, determined to remain there forever rather than fly one mission more than the thirty-two missions he had. Ten days after he changed his mind and came out, the colonel raised the missions to forty-five and Yossarian ran right back in, determined to remain in the hospital forever rather than fly one mission more than the six missions more he had just flown.

Yossarian could run into the hospital whenever he wanted to because of his liver and because of his eyes; the doctors couldn't fix his liver condition and couldn't meet his eyes each time he told them he had a liver condition. He could enjoy himself in the hospital, just as long as there was no one really very sick in the same ward. His system was sturdy enough to survive a case of someone else's malaria or influenza with scarcely any discomfort at all. He could come through other people's tonsillectomies without suffering any postoperative distress, and even endure their hernias and haemorrhoids with only mild nausea and revulsion. But that was just about as much as he could go through without getting sick. After that he was ready to bolt. He could relax in the hospital, since no one there expected him to do anything. All he was expected to do in hospital was die or get better, and since he was perfectly all right to begin with, getting better was easy.

Being in the hospital was better than being over Bologna or flying over Avignon with Huple and Dobbs at the controls and Snowden dying in back.

- Joseph Heller, Catch-22, New York, 1961

[Since everyone always quotes the famous passage early on in Catch-22 in which the title is explained, I thought I'd quote a completely different passage, in this case being a description of Yossarian's campaign to cheat fate by inventing medical complaints to keep himself grounded. But just in case you're unfamiliar with the concept of Catch-22 - surely one of the most memorable and important comic novels of the 20th century - here's a trailer from the 1970 film version in which Doc explains the catch to Yossarian (Alan Arkin). But you really should read the book - it's tremendous from Chapter 1]