精神病人思维广弱智儿童欢乐多
[jīng shén bìng rén sī wéi guăng ruò zhì ér tóng huān lè duō]
The mind of a mental patient spreads wide whereas simple-minded kids experience pure joy. It uses extreme examples to show different levels or kinds of living, like broad-minded people versus easy-going and ignorant happiness.