At least while you're working, as opposed to relaxing... Personally, when I'm relaxing, as in socialising, or watching TV, I don't want to be sitting up straight. My body is perhaps tired but my mind wants to stay up while, so I treat it as though I'm in bed already. I use cushions for total support, changing position every now and then. But sitting to work, as in eating or desk work, is different because you're using your body. In this case sitting upright, or as close to up