Well he was blessed with a photographic memory. So he read a 10 volume history of the world in German when he was a kid and could recite pages verbatim in his 40s! I think he enjoyed military history a fair bit (he read the history of the Peloponnesian Wars) and war games. This probably played into his later interest in games and explains partly why he formulated game theory. Like a lot of mathematicians at the time, they wondered whether maths could help bring peace. They hoped they could use maths to resolve conflicts. Emanuel Lasker, chess grandmaster and a pupil of Hilbert, said the institutes dedicated to the 'science of contest' would ‘breed teachers capable of elevating the multitude from its terrible dilettantism’ in matters of negotiation, transforming politics completely, and ‘aid the progress and the happiness of all humankind’.

He also loved reading novels-Dickens, for example-he was able to recite huge chunks of A Tale of Two Cities. But really he seemed to live and breathe maths, outside the time he spent driving badly at speed and partying.

One of his main blind spots was...himself. He didn't keep a diary though you get some glimpes of the man through his copious letters (his love letters to Klara Dan are remarkable!). But even here, he'll be talking about current affairs, then veer off into a 6 page maths proof! I don't think he was given to analysing his own feelings much...