There are plenty of movies where I've come out thinking that I'll never get those 2 hours of my life back. I do apply this logic to commute time though. $salary - $commute = $takeHome. Some jobs are not worth it.
I also agree 100% with the time cost on something you're wanting to learn is a sunk cost. After all, it's an investment in yourself. Even if it fails, you now have that experience of what not to do if presented the chance again.
In The Netherlands you get a large part of your travel costs reimbursed by your employer. How large it is, there are legal upper limits to avoid "untaxed extra payment".
If you can travel by public transport, part of the time of your commute is akin to leisure time. But I have big issues with failing to focus, especially if I gotta switch transport multiple times or run to make it or its crowded or...
My limit of commute is basically an hour, and if I don't get the costs reimbursed I simply do not take the job. It is bad enough that I lose that time as it is (as I argued above, it is hardly akin to leisure time).
As for the topic at hand, I've spend a good amount of time and money on e.g. old UNIX hardware (such as SGI Indy/Indigo 2/Octane, Sun Ultra 10, and some DEC Alpha machines) back in the start of this millennium. It was costly and bad for my electricity bills, and it took me a lot of time to play around with old platforms. I had a lot of fun though. And I'm not sure you can benchmark "fun". Nowadays, with solar energy on the rise, it might actually matter less to have these machines running. Except for in the summer. The additional heat would kill me.
Learning to think about time spent on getting ready for work and commuting to and from work as a direct extension of my working hours changed the way I looked at jobs and approach salary negotiation. It's so easy for someone to ignore that cost if they haven't thought about it, and so hard once they have thought about it :)
I also agree 100% with the time cost on something you're wanting to learn is a sunk cost. After all, it's an investment in yourself. Even if it fails, you now have that experience of what not to do if presented the chance again.