Play is not just essential for kids; it can be an important source of relaxation and stimulation for adults as well. Playing with your romantic partner, co-workers, pets, friends, and children is a sure (and fun) way to fuel your imagination, creativity, problem-solving abilities, and improve your mental health. And actively playing with your kids will not only improve your own mood and well-being, it will make your kids smarter, better adjusted, and less stressed.