I've tried and hated everything.Yes, it's bad to use exercise as punishment. Find some kind of exercise that you enjoy doing. You're not going to do it if you don't find it enjoyable. Whether it's dancing, walking, doing yoga, playing a team sport, swimming, jogging, biking...find something that you enjoy spending time doing. For me, I like hitting a little ball against a backstop with some kind of hand-held item. And I prefer to do it alone, without a team mate (I tend to prefer solitary exercise). This means that my kind of exercise is either hitting a tennis ball against a backstop on my own, or raquetball court on my own, not playing against another player, but just testing my own mettle by playing against myself.
I also have to admit that I like repetitious, mindless exercise where I don't need to expend a lot of thought. This usually means solitary exercise on a treadmill or stationery bike at the gym. I know this is not the preferred method of exercise for many people, but it works for me, so that's what I do. I pop in my iPod earbuds, zone out to some great music and not think about anything for a change. So what kind of exercise do you enjoy doing?