Every once in a while, something happens or we meet someone and the experience is so powerful, it forces us to stop for a minute and think - and maybe readjust how we feel about our lives and the world around us.
CBS News national security correspondent David Martin reports on an amazing, 23-year-old man from Staten Island, N.Y., who lost all his limbs fighting for his country, but never gave up his American Spirit.
Sooner or later it had to happen - a soldier losing all four limbs and yet surviving. It happened to Brendan Marrocco on Easter Sunday of 2009 in Iraq, when his vehicle tripped a roadside bomb.
"It just took both arms, my left leg off completely and my right leg was still attached a little bit," Marrocco said, "and killed my gunner - my best friend."
Then there's that nasty scar on his neck.
"Yeah, I severed my carotid artery," Marrocco said. "That alone should have killed me."
Carotid artery severed, both arms and left leg completely off - why didn't he bleed to death? The answer is a gruesome irony: the heat of the blast instantly cauterized the same wounds it had caused.
"I was barely bleeding from them," Marrocco said. The same weapon that took half his body saved his life. Just barely.
"I wasn't expected to live," Marrocco recalled. "I died three times and came back." No pulse. "Flat-out dead."
Read More about Brendan Marrocco at his Website
Michael Anaya, his gunner and best friend, was killed, even though he was not as badly wounded.
Is Marrocco the luckiest guy on Earth or the unluckiest?
"A little bit of both I guess," he said. He's not bitter. He calls himself "very fortunate."
What he has is a very good sense of balance -- physical and emotional -- vowing, "I will not sit down and let my injuries take over my life."
Just ask his physical therapist Luis Garcia.
Working with a quadruple amputee is "a lot easier than I thought it would be," Garcia said. "Because of his character and his personality."
Brendan cracks jokes only he can get away with.
"There's times where he's just 'give me a hand. Can I just get a hand?' joking around," Garcia said.
But there is no sugar-coating his wounds. He has had to learn to walk without arms for balance or to break a fall.
He calls the missing arms worse "by far." "Without legs you can still be independent. You know, without arms there's so much more you can't do," Marrocco said.
He can - and has - still hit the ski slopes. And he's met Tiger Woods. It's not clear who's taking inspiration from who in the photo. After meeting Marrocco, it's hard to take anything in your own life for granted.
"I love walking," said Marrocco, who is now fitted with artificial legs. I'm just not at the point where I can wear them all the time. I wish I was." But he say's he'll get there: "No doubt about it. I will."
He uses a virtual reality chamber to practice walking on real world terrain.
He still needs a wheelchair for everyday locomotion. And the woman often seen pushing him is not a nurse. It's his fiancée, Kate Barsto. They met at Walter Reed.
"He's such an incredible person and people don't need to feel sorry for him," Barsto said. "He's going to do some great things in his life." Marrocco may never have a "normal" life in terms of his physical abilities, but, Barsto said, "He's better than normal to me."
And what else does he plan to do with his life?
"Get my bachelor's degree and master's degree and try and go maybe into the FBI or CIA," Marrocco said. He believes his injuries happened for a reason, part of God's plan.
What does he believe that plan includes? "So far it seems to be to inspire people and touch lives," Marroccco said.
It also seems Brendan Marrocco didn't just survive - he thrived.
Copyright 2010 CBS. All rights reserved.
David Martin is CBS News' National Security Correspondent.