For many, it completely depends on time spent at work and effort spent at work. I've been on both sides. If you spend a lot of time and effort at work (not a bad thing), your desire is diminished outside of work. However if you don't have to spend a bunch of time/effort at work, there is time/effort available. Granted, even that relies on whether you enjoy it over other things, but you shouldn't be shocked.

I find the programming that I do for work to be fun. I consider this one of the blessings of the career for me. Solving/reproducing bugs and deciphering other people’s code is intellectually stimulating similar to sudoku or crossword puzzles.

If I weren’t working such long hours currently, I could see myself creating a webpage or writing an app, or playing with arduino for fun. But as it is, I’m pretty much tapped at the end of the day. I don’t really have the mental energy (or solid blocks of time) to accomplish much of anything.

I could definitely see myself doing it if I were in a situation where I didn’t have to work. (If I won the lottery or I had a rich wife/parents or whatever).

I’ve been doing this for about 10 years.

True, but am able to get excited about something that "scratches an itch," or will improve longterm productivity. Your commute might also be killing some enthusiasm, I know it did when I went in to the office.

If I have an interesting problem, I honestly don't mind.

That has happened once in the last 15 years that I can actually remember.