It's a humanity thing, there are people who are quite imaginative and for guys if a girl smiles at you they think those girls like them, blah blah, same concept
In Japanese they dont say the subject or anything often so instead of saying "I love it!" you could just say "love!" and that can be misinterpreted as "I love (you)!" I think this series is korean but east asian languages have some similarities so maybe they run into the same problem? Im guessing