This summer I've been in a car, on a train, and on a plane traveling. The seats are just plain uncomfortable and if I don't modify them in some way, my back and hips feel terrible when I finally get to my beautiful destination.
I had a conversation with one of my clients about his squatting and correct form last week. I have seen a lot of variations but many of them are bringing people closer to injury. I find that many people will sacrifice their form in order to "get lower" or do what the other people at the gym are doing.