But how? How could anyone's enthusiasm not be diminished by failure? Not even a little bit? If there are really people like that, that sounds like a genetic advantage.
No matter what happens, I'll still be breathing tomorrow, unless I die in which case it doesn't matter anyway.
I approach everything in life under the assumption that I'll reach my goal. Some things go wrong, of course, but mostly the world gets out of my way and lets me pass.
A "failure" means that your success doesn't lie with them. Move on.
Also, take some time to think about WHY you have the goals that you do. Are they really what you want, or just something that other people told you to want? The world is full of successfully miserable people.
Up-voted so I feel less guilty stealing that phrase!
To read way too munch from your comment. "that sounds like a genetic advantage" is a fixed mindset way of thinking.
Some people think differently to you and I, really differently, and have no ability to empathise with others. Not being loved as a child is no genetic advantage though.