Just spend 1 minute doing sit-up, push-up, move your hands, feet and your neck slowly every morning always make my day better if I can't afford to jog for 30 minutes in a park. If you do jog, try to find a park (I usually do it in a park with basketball court so I can run in a square). I get the sunlight and the fresh air. Avoid the gym unless you are going to do weight-lifting.
Jogging is great in a park, but for a lot of people a lot of the time it's not practical because of either the weather (running isn't great fun in the rain / snow) or safety (some people can only find time to run after dark and for women that isn't sometimes safe).
So it's bad advice to say avoid the gym, as people should be finding any opportunity to exercise, not more excuses / rules to tell them not to.