[crispyalmond]

I wouldn't consider projects which make $0 to be failures, unless your intent was to make money from them. I like making tools/games in my spare time with no intention of profiting from them. I simply enjoy the programming aspect way more than any monetary value. I'm not saying that I wouldn't like the money, but it's not my primary focus for making these projects.

[bluewalt]

That's a very strong advice to remove irrelevant guilt. Many people bind success with money. That's just one thing you can benefit.