Not to burst your bubble of optimism here but failure can be bad too.

Yes, to achieve greatness in life, we all need to strive to better ourselves, and if we make mistakes, we fix them. But that's usually for tiny mistakes.
Like if I ate my lil' bro bro's Taco Bell, then he'd probably cry, but I can fix that to better myself and just buy him a new Taco Bell.

But if a brain surgeon makes a mistake in surgery, then someone has to pay the price whether it's the doctor or the patient no?

Ultimately, someone is gonna get hurt. That doctor could lose reputation and trust. So, can you say that he/she is achieving greatness?