Is there one? If you have a story centered around one character, do you have to have a love interest? Is it necessary to the plot or character growth at all? I've been trying to think of movies or books or comics I love that I love that don't have a love interest involved somehow, but I can only come up with like less than 5 things. I'm also counting stories where two characters have sexual or romantic tension throughout the fiction even though nothing came of it. What do you guys think?
There are more than that that don't have a love interest but most stories have love interests. It's kind of weird but it makes sense because most people want to find someone special even action movies (but the Transporter films lack a love interest, I think...)