Then you start taking into account that you hate physical exercise (I've tried group sport, gym, running, swimming, walking etc...) and you start treating it like a job and instead of being relaxing is another chore. So not only I'm doing something just for maintenance, but it feels like work (in my case, it is work) and while I'm sweating at the gym I'm not doing something I'm really interested in and after the supposedly beneficial exercise my mental energy is too depleted to do the things I really want to do.
I'm never been more miserable than when I exercise regularly: "nothing" you say, uh?