Bill Gates in his own blog:
Dad wrote me a letter on my 50th birthday. It is one of my most prized possessions. In it, he encouraged me to stay curious. He said some very touching things about how much he loved being a father to my sisters and me. “Over time,” he wrote, “I have cautioned you and others about the overuse of the adjective ‘incredible’ to apply to facts that were short of meeting its high standard. This is a word with huge meaning to be used only in extraordinary settings. What I want to say, here, is simply that the experience of being your father has been… incredible.”
I know he would not want me to overuse the word, but there is no danger of doing that now. The experience of being the son of Bill Gates was incredible. People used to ask my dad if he was the real Bill Gates. The truth is, he was everything I try to be. I will miss him every day.
More here.