I drive with radio and ac 99.9% of the time. The other .1% is sitting at a light - I adore turning off everything and sitting in the silence, knowing that my car is ready to move by lifting my foot from the brake, while hearing all of the ICEs surrounding me rumbling and polluting the area. It's totally a feeling of superiority. Not that I don't feel superior to most people most of the time anyway! But in my FFE there's a physical embodiment of feeling and being different.
To answer the original question, though: storage. I miss easy access to my garage door opener and coin slots. On the list but just not major is the tiny back seat. There's just no room back there if I'm in the best driving position for my body.