Grigori Perelman, Russian mathematician

declined the highest honor in math- the Fields Medal ( equivalent to Nobel Prize) in 2006.  He was the first mathematician ever to decline the Fields Medal.

The reason as he anounced : "I’m not interested in money or fame. I don’t want to be on display like an animal in a zoo. I’m not a hero of mathematics. I’m not even that successful; that is why I don’t want to have everybody looking at me.”

4 yrs later, he turned down 1 million $ Clay Millennium Prize, said:" “I have all I want ” through a closed door.

Purest of the purists: http://nautil.us/blog/purest-of-the-purists-the-puzzling-case-of-grigori-perelman