I think calling "play" only half a habit belittles the value of having fun; I remember things better when I'm having fun. I am more likely to pay attention to things I enjoy, and I do not consider playing "work."
I took piano lessons for 7 years, and I never thought that practicing was "work" until the very last year. I think I got to be pretty good at the piano because I didn't consider exercises or practicing "work."
Beginning with the end in mind often prevents me from enjoying the learning experience, because all I'm concerned with is my intended "destintion;" getting there is half the fun, and staying aware of other possible uses for what I'm studying can make the process more interesting.