Healthy but Hurting

After about the 48th ab crunch tonight in fitness class, I wondered: "If exercise is so great for the human body, then why the frick does it hurt so much?" Personally, I think a lot more people would do it on a regular basis if pain wasn't involved. Seems like yet another design flaw in the human system. Gosh, high blood pressure doesn' t hurt a bit but 60 second wall squats and floor planks hurt a lot. Hmmm, which one should I choose? Gaining weight from sitting on the couch with a bowl of ice cream watching a rerun of Scrubs for the 5th time doesn't hurt either but doing my bicep curls and tricep lifts does. And it doesn't hurt at all to have my bones lose density but walking up & down the hills around my house does. Being in bad shape = no pain. Trying to be in good shape = pain. That's just WRONG!