I don't expect someone to have the exact same interests, but it certainly helps.

Before we got together, my SO had interest in a very niche hobby of mine that usually is predominated by retirement aged-women(dog sports). To find a man in his early twenties interested in it is practically unheard of, so I was hooked the moment he asked where I trained my dog. I like that he understands that world. One of my concerns was that future partners would think I spend too much time training or at competitions, but having someone who participates as well helps a lot.

I also got him started in rock climbing and now it's become a fun activity that we can do together every week.

I care about him for reasons beyond those interests, but I really enjoy having things in common.