Some days you just have to accept that what you accomplished was that you learned a few new ways how not to make a light bulb.
You didn’t finish a project or accomplish a goal. Maybe you didn’t even get closer in the sense that you’re any deeper materially into the problem.
But if your back hurts, your eyes are sore, and your brain is fried, then guess what – you learned something. Maybe it was just where the wild animals are, but you learned something. Some trap to avoid.
Avoid enough traps and you get where you’re going. Get some rest. Plenty more traps tomorrow.
The Opportunity Machine 