This is going to be a very political blog. Please excuse it if it is too boring. You'll get over it.
There have been recent discoveries of JFK tapes from 1960. It's not told when these tapes were found, but they were made three days after former president John Kennedy announced he was running for president. These tapes are about his doubts of winning and his worries of losing. In these tapes, he's heard saying that he does not like doing a politician's job, but in order for major change, presidency is where the change is at. He's quoted saying "The center of action, it's the presidency" in these tapes. However, he is also quoted saying "I'd rather read a book on the plane than talk to the fellow next to me" in regards to disliking what politicians do.
All in all, these tapes reveal self-doubt, yes. But they also reveal a level of confidence that is rarely seen. Here is a man who knew he may not have won the election, but he still chose to run for it and "go for the gold".