Happiness-based project appraisals

"I’m willing to work for free if it’s the most exciting thing ever. If it’s challenging, which in turn enables me to learn from the experience, which in turn makes me happy"

So, have you actually ever done this? Or are you just "willing?"

I'm a freelance developer and I would never do this. Client work is rarely fun, but for me it beats my alternatives.

Here is a better idea I think. Rather than working for free for someone else, find your own project which makes you happy and work on that project for free. Then, if you can make a business out of that project, it's your money and your business. That's much better than making someone else money from your labor.

Another quote:

"If you’re project is both interesting and relies on solid UX to work, then you can compensate me with something else than cash (equity?). I will come through, it’s my expertise."

Equity (part ownership) isn't working for free. In fact, it could be much better paying than even your highest rates (but odds are probably against it.) I don't think this point should be lumped in with your "free" or "lower rate" points.

Also, all the items under "But you’re getting ripped off!" aren't very good reasons if you are in well enough demand to always keep busy. All of those bulleted items you listed off in that section are just as much benefits from paid projects as they are for free projects, so you might as well be getting paid. There might be very rare exceptions though (building a project for a rockstar running a non profit or something.)

Money doesn't buy happiness, but it gives you a powerful tool and more options to find happiness. You are running a business, so run it like a real business!