Yeah and that design and insight is the tiring part and while fun a bit less satisfying in the way that writing a nice bit of boiler plate or populating the struct members for your data type can be. One thing is you can work on design and insight while taking a good walk around the block, which is nice.
I spend that time mostly on the sofa, or in front of a whiteboard. Or sometimes a live brainstorming. Typing code is actually relaxing. What looks like relaxing is actually hard thinking.