What prevented George from taking advantage of Lennie? What does this tell us about George?

George says that when he first began traveling with Lennie he found it funny to play pranks on him. One day he ordered Lennie to jump in a river even though he couldn't swim and Lennie unthinkingly obeyed. After George fished him out, Lennie was completely grateful, having forgotten that George had ordered him into the river in the first place. After this episode, George decided against having fun at Lennie's expense. This tells us that George is a compassionate and caring man.