I know it's a football forum, but if I was ever to give any advice to any athlete about who to look at to help make their life better, Nadal definitely would have been one of them.
Tennis was always a kinda love/hate relationship with me on multiple levels. I remember trying to get back into tennis and watching a match with Marcelo Rios and just being so disgusted. Federer was a little too proper for me. Seeing this Spanish kid with the long hair and crazy capri shorts was so unique and just played so hard. I just wanted to see him beat Federer at Wimbledon some day. There was this realization that Nadal probably wouldn't last very long because he was so hard on his knees. Never expected him to last as long as he did.
Over time, what was truley impressive to see with Nadal, was how hard he practices every time out, not just in the matches. He's never broken a racket. The amount of respect he showed opponents was always impressive and honestly unique at the time. What was also impressive was how dedicated to family and friends he is and how much he loves his country.
There have been so many great athletes out there, but if there was EVER someone (outside family) to look at to try to learn how not just be a great athlete, but a great person, I think you could put Nadal up high on that list.