Thankfulness differs from gratitude in its active expression - it's gratitude put into words or actions. Studies of workplace teams show those who regularly express thankfulness perform 19% better. Brain scans reveal that both giving and receiving thanks activate the hypothalamus, which regulates stress. Elementary schools that implement thankfulness circles see reduced bullying incidents by 35%. The magic lies in specificity: "Thanks for staying late to help with the project" lands better than a generic "good job." Evolutionary biologists suggest thankfulness developed as social glue - it strengthens relationships more effectively than material rewards. Try the "thank you challenge": express detailed thanks to three people today and notice the ripple effects.