It's interesting -- I have sort of been coming to the same conclusion myself. I work full-time and have a family. I have ideas for side projects and learning new stuff but on any given day, after work and activities with kids I usually don't feel like spending the hour or two of spare time I might have on something that takes a lot of mental engagement. Sometimes on weekends, if there isn't a lot else going on, I'll spend a few hours on a Sunday afternoon on that sort of thing, but beyond that it generally doesn't happen.

Of course I then feel bad that I'm not getting things done that I want to do, but have lately been more inclined to think that I'm already at capacity and it just isn't going to happen unless I trade off something else. So now I'm evaluating whether I would really get more reward out of pursuing these extra activities at the expense of something else, or if I should stop even thinking about it and just enjoy what is already happening in my life.