If you don't get exercise guilt, lucky you!
I would say 90% of my friends feel some sort of guilt if they can't do their planned exercise for the day, and I am definitely at the top of this list. So why do we feel like this? I think it's a combination of a few things.
So as much as it looks crazy on the outside that someone can be so upset just because they missed going for a thirty minute run, on the inside it means so much more to them.
Now as I struggle through my day of being injured and not running (praying that my calf is fixed miraculously today), I am trying to direct my energy towards something that will benefit me in different ways, just without sweating so much. Oh... and maybe the odd workout that is adjusted to only using one leg!