There are proverbs that involve shojin (small person, small character, physically short person, Issunboshi) such as, if a small person sits idle he will do something that's not good, which means that if a person of small character has too much time on his hands he will do something that's not good.
小人（しょうじん、小人物、背の低い人、一寸法師、）の諺は、小人閑居して不義を為す…小人物は暇だとついよくないことをする。