One of the most interesting motifs in Part I is presented through the character of McMurphy and how he obviously is so different to the rest of the patients on the ward. One of the aspects of his character that makes him so different is his laughter. Note how Bromden describes his laughter in the following quote which comes as he is first introduced:
He stands looking at us, rocking back in his boots, and he laughs and laughs... Everybody on the ward, patients, staff, and all, is stunned dumb by him and his laughing. There's no move to stop him, no move to say anything... Even when he isn't laughing, that laughing sound hovers around him, the way the sound hovers around a big bell just quit ringing...
McMurphy's ability to laugh in such an open and loud way separates him from everybody else, as the other patients are not able to laugh. They are only able to snigger behind their hands. For McMurphy, laughter, and the ability to laugh at life is part of healthy living, and being able to laugh is something that allows one to cling on to sanity in a world that often presents itself as insane. After the fishing trip, it is highly significant that some of the patients are able to laugh for the first time, which marks their recovery.