The whole idea of mindfulness is all about having a second-level monitoring of your thoughts and being able to recognize them as being negative or harmful before they become a part of your being, before they become some kind of action like writing an angry letter to someone or speaking too strongly to someone.
O painter, take care lest the greed for gain prove a stronger incentive than renown in art, for to gain this renown is a far greater thing than is the renown of riches.