An interesting hypothesis, that as we turn our likes into habits, we lose our emotional connection with them. In essence, we get less happiness from these special occurrences.
http://www.smh.com.au/lifestyle/life/love-it-then-dont-make-a-habit-of-it-20141001-10ogzz
So if you want to continue to like something, the writer seems to indicate you shouldn't do it too often.
I'm of a different mindset on this: if it's enjoyable and positive, then you should be driven to do it more and more, and the prospect of doing it "more" to get a reward is not a negative idea.
Of course, there is the "everything in moderation" advice which has merit. But I love going to the gym and lifting weights; I really do! And I know I can do it "too often" and end up injuring myself. But it's a habit to go three times a week, and I enjoy it just as much every time, even though it's a habit.
So have a read and see what you think!