It's official now: after finishing my first round of P90X I also graduated with my first round of Insanity. A lot of sweat and calories were lost. However I have to admit that I think Insanity is more suited for people who actually still have to lose numbers on the scale. Even though my cardio has improved a lot, I hardly saw any changes in my body composition.
I personally think excuses are the single most important factor to keep us from reaching our goals. It's easy to find an excuse for everything: Doing the dishes? Nah I do it later..
However, finding excuses to not get fit is probably the one thing people find the most variations for:
It's too hot, I am not feeling well and my favorite one: I can't do this because (insert reason).