First of all, there's a difference between being less comfortable and uncomfortable. I said I was never uncomfortable on my bike, I didn't say it was equally as comfortable as every other state of being.

When I used to ride in cars as a child it was incredibly uncomfortable because I got car sickness. When I started to learn to drive it was uncomfortable again because of all these weird controls and the stress. I'm sure many of us would find it uncomfortable merely to be inside a car had we not grown up with them from a very young age. I, and everyone else, learnt to find cars comfortable just as I learnt to find bikes comfortable.