Model trains, stamps, and books.

Unless your name was Henry Cavendish - Then you’d be making amazing scientific breakthroughs and not tell anyone, only to get credit posthumously after someone reads your lab notes.

He conversed little, always dressed in an old-fashioned suit, and developed no known deep personal attachments outside his family. Cavendish was taciturn and solitary and regarded by many as eccentric. He communicated with his female servants only by notes. By one account, Cavendish had a back staircase added to his house to avoid encountering his housekeeper, because he was especially shy of women.