Compare to worse conditions to be grateful

"It put me upon reflecting how little repining there would be among mankind, at any condition of life, if people would rather compare their condition with those that are worse, in order to be thankful, than be always comparing them with those which are better, to assist their murmurings and complainings."

- Daniel Defoe, Robinson Crusoe, p. 165

Discontents due to lack of thankfulness

"All our discontents about what we want appeared to me to spring from the want of thankfulness for what we have."

- Daniel Defoe, Robinson Crusoe, p. 130