Yes, if you aren't moving forward then you are regressing. You must grow to be healthy. Stagnation is depression. Successful (and 'happiness' based on 'happenstance' is another) is a word you have to be careful with because it means different things to different people, e.g. to some successful means making money others it means being happy through progress. Seeking "well-being" through progress is the key ... Tony Robbins makes this point clearly too.