No one would have crossed the ocean if he could have gotten off the ship in the storm.
When I was research head of General Motors and wanted a problem solved, I'd place a table outside the meeting room with a sign: "Leave slide rules here." If I didn't do that, I'd find someone reaching for his slide rule. Then he'd be on his feet saying, "Boss, you can't do it."
Failures, repeated failures, are sign-posts on the road to achievement. The only time you don't want to fail is the last time you try something (and it works).