I know this is obvious to many, but endorphins are pretty awesome and could be very addicting. I went for a run today; and what I mean by run is a walk/jog type of workout where my #C25K app on my phone tells me to run for a minute and walk for 1.5 minutes. After 30 minutes of this I feel like a million dollars and could fully see an addiction coming on.
Exercise = Endorphins. Endorphins make you happy.
today is a good day, I will keep it that simple and not overthink it..... my cape is on today;)