Yogic workout?

I'm a fan of fitness. I've been raised to enjoy hikes (though lately that hasn't stuck), to take after dinner walks, and to sign up for dance classes. This past weekend I was at a hotel with my family, and I was that person looking for a gym. Being anti-fitness is like being anti-chocolate--never mind the fact that they totally contradict each other. I feel the best after working out--like I can leap off a building or two, and karate chop some wood. I can do neither of these things, but lunges do strange things to my brain. But once the need to exercise trumps the enjoyment of said workout, that's when fitness fanatics get worrisome.
As a student of yoga, I'm constantly feeling the tug of war between mind and body. The ultimate goal of yoga is to merge the two as one state of being, but living in a culture of calculations, once I've done ninety minutes of meditative sweating, I can justify eating that devilish looking cupcake. And just another bite--maybe another half--three cupcakes later, the last thing I have is peace of mind. All I can feel is sore calves and no motivation to do another round of sun salutations.
In the west, yoga has become very much about "no pain, no gain," and "get that hot yoga body in thirty days! Ten days! Ten seconds!" It's become a selling point in gyms--a product, rather than a way of living. Jillian Michaels, workout guru who is known for her hard-ass exercise videos, came out with a yoga DVD. It was the first time I'd heard "cardio" in between postures. By the time I was doing Warrior III to the sound of "who's your daddy?" it felt more like I was stretching to a porno video than a yogic one. The video ended abruptly; there was a rushed cool down and Michaels skipped Savasana--corpse pose--and I rose from my yoga mat feeling like I'd been punished. In Eastern cultures, the asanas (postures)  are just a teeny tiny portion of what makes yoga. Bhakti yoga totally eliminates the poses; it is purely about the worship of a higher being. Ashtanga yoga is physically exhausting, but its eight limbs include breathing, and the enlightened state.
So should yoga take the place of other exercise? Physically, it's enough of a workout to keep me healthy, but if I rely on the asanas for flat abs--or at least the hope of flat abs--I'm back to using yoga for superficial purposes. Already, I can see the shift in what I'm thinking during my yoga practice. During my month at Shoshoni, my mind wrapped around the alignment of my poses, and how to keep my breathing smooth and relaxed. At home, I do upward facing dog while thinking about how many calories I'm burning. 
What's nice about yoga is that it recognizes that we feel different each day. Some mornings I jump out of bed, ready to pull out my yoga mat, but sometimes I just want to curl under my covers and read Tina Fey's memoir for the millionth time. My body can be a lot smarter than my brain sometimes; I just have to listen to it, and accept the fact that I'm not going to feel like sweating seven days a week. Relaxing isn't a sign of weakness, or lack of devotion to a yoga practice. In religions where yoga is practiced (yoga itself is not a religion), you contain Shiva--or the enlightened being. Disrespect to yourself, your body, is disrespect to the world around you. And sometimes I just need that day to watch a string of Friday Night Lights episodes with a bowl of ice cream. My yoga practice is a good workout, but it's not the main point of my hour on the mat. It's about tuning into myself, and being more open to understanding both my strengths and weaknesses.

How do you, dear readers, keep yourselves fit and healthy? How do you balance the physical and mental parts of yoga? Enjoy exercise--but don't punish yourself for lazy days. :)

Namaste.