Нет тяжелее бремени, чем безделье-

You get very tired when you have nothing to do

Cf: The hardest job is no job (Am.). The hardest work is to do nothing (Br.). Не has hard work indeed who has nothing to do (Am.). Не has hard work (works hard) who has nothing to do (Br.). It is more painful (pain) to do nothing than /to do/ something (Br.). The lazy man takes the most pain (Am.). A lazy man works the hardest (Am.)