Today at work I bought some shopping, and took them home in my backpack on my motorbike. My bag was quite full and heavy, which caused a strange change to my riding. I had my bag straps quite tight, and hence it made my sit up quite straight, I couldn't lean or crouch forward. The bag was able to rest on my pillion seat, so it wasn't a weight. But it felt like I was more rigid, as if the base of my spine was fused to the bike. This changed how I rode. I seemed to go slower, but also be less stressed while riding. I also had to make the whole bike lean, as opposed to moving just myself around the bike. It was quite a pleasurable and relaxing way to ride.
Right now I'm reading Jupiter's Travels by Ted Simon. Riding like that makes me feel like I'm on one of those long tours, with my bike laden down with gear and not a care in the world.