1. Increased energy – somewhat counter-intuitive since exercise expends energy, but it's true

2. Improved sleep – as long as you're not exercising right before bed (see #1)

3. Decreased symptoms of depression and/or anxiety – via increased serotonin, norepinephrine and dopamine.  For more on this topic I highly recommend the book Spark: The Revolutionary New Science of Exercise and the Brain by John J. Ratey, MD.

4. To nurture your organs – pretty much every organ in your body benefits from movement, including your heart, lungs, brain, and pancreas. 

5. It's fun – if you don't relate to this you're doing the wrong type of exercise.  Try something new!  It should be enjoyable and feel good.  Perhaps something with a social component will do the trick.