Then don't. There are only so many hours in the day, this is about fitting as much as possible into them. If you want to take a break during your shower, or go to get coffee with friends every day, that's cool, but there are people with many things going on and they enjoy doing it all. To each their own.

I think this is mostly being talked about in the context of starting a company or a side project. I can understand that you would feel that way about a day job and of course it's completely optional, but if you don't feel eager to work on a project that you've taken up your own initiative to start, then that is probably worth re-examining. You won't always feel that way, bit most of the time, at least. I'm currently working on a new product idea and I literally could not stop myself from thinking about it during my free brain cycles if I tried.

This. It's true that when you have a child you get used to plan and 'prepare' code in your head and then write it down in small slots of free time. But the result of doing this is that you are working all day really, your mind is not with your family or house duties, it keeps working on background, anxious and eager to put your hands down on the keyboard. And that's not nice. And it's very difficult to balance, I'm struggling with this on a daily basis.

do it in your commute or during boring "dead time" instead where relaxation is almost inpossible