the happy door 快乐之门the happy doorhappineis like a pebble dropped into a pool to set in motion an ever-widening circle of ripples. as stevenson has said, being happy is a duty.there is no exact definition of the word happiness. happy people are happy for all sorts of reasons. the key is not wealth or physical well-being, since we find beggars, invalids and so-called failures, who are extrem..