His rival Samuel Reshevsky said that Keres failed to become world champion because he lacked a killer instinct and "was too mild a person to give his all in order to defeat his opponents. He took everything, including his chess, philosophically. Keres is one of the nicest people that I have ever had the pleasure of meeting. With his friendly and sincere smile, he makes friends easily. He is goodnatured and kind. Yes, he loves chess, but being a human being is his first consideration. In addition to chess, Keres was interested in tennis, ping-pong, swimming, and bridge."