How do their likes and interests affect their character?

I’ve learned a general rule that often applies in writing and real life: if someone likes only old music or old movies, refusing to try new stuff, they are not open to change. How can you reflect their personality in what they like? Are they studious and keep books in their car in case of a long drive-thru line? Do they always keep a baseball in their glove compartment in case of a game? Showing inanimate objects’ relationships to the character can show a lot of their personality.