This is an excellent post.

I'll toss in another example: volunteering vs. donating to charity. People like the idea of volunteering, even when they could do more good by working longer hours and donating the money to charity.

When I first entered college, I had the idea that I'd go to med school and then join Doctors Without Borders. Do a lot of good in the world, right? The problem was that, while I'm good at a lot of things, biology is not my strong suit, so I found that part of the pre-med requirements frustrating. I ended up giving up and going to grad school in philosophy.

To maximize my do-gooding, I would have been better off majoring in Computer Science or Engineering (I'm really, really good at math), and committing to giving some percentage of my future earnings at a high-paying tech job to charity. Alas...

Now whenever I meet someone who tells me they want to go into a do-gooding career, I tell them they'd be better off becoming lawyers so they can donate lots of money to charity. They never like this advice.