In pg's latest essay, he mentions toughness as "a quality you need to win". He also has mention how many of the founders have got a lot tougher since they began to work in their start up. So I'm guessing there is something you can do consciously to get tougher.
References [1] - http://www.youtube.com/watch?v=NZxGYtOXUP4
Start to observe that failure is actually less likely than you thought it was.
Repeat until desired level of toughness is acquired.
When you're out there, you're getting flung around, it's cold, it's wet, watches are 3 hours on 3 hours off unless there's work that needs to be done, in which case you just have to get on with it. The needs of the boat come first and the skipper's word is law. Heading upwind to counterbalance the sail, the crew sits out on the rail - when I say 3 hours off that can mean, clip yourself on and sit out on deck in the rain and the wind and the waves breaking over the deck and pull your hood down and try to snooze. If not you can go below but if it's rough you probably won't get much rest - I've had friends break arms, collarbones below decks. It's a brutal sport, physically and mentally.
But there isn't the option to say, stop the boat, I want to get off. You're out in the middle of the ocean, just you, the crew and the boat. You're on your own. And unless everyone has their shit together, everyone is in danger. Your friends are in danger. You have no choice in the matter, yet you chose to be there, of your own free will. Yeah, the first time out will show you who you are, and if you need to change and you can change, it'll happen there too.
Something invigorating about the whole process -- makes you feel alive.
I got no respect for tourists who go bungee jumping and think they're "extreme" when someone else has made sure they're actually perfectly safe.
My thing is flying. As an instrument pilot, it's all in my head. You go up in a dark, rainy night and it's just you and the airplane. There are no "easy" buttons. You're managing dozens of variables real-time all the while keeping the plane level. In hard IMC on a low approach, there's no goofing off -- even for a couple of seconds. You get those "what the heck am I doing here" moments, but then again, there are experiences that I've had that you could never reproduce. Either your shit is together or -- you're dead. It's a mind game where the stakes are your life.
Good stuff.