Nobody likes or loves a whole person. That's right, you heard me. They like or love a part of that person... Maybe a lot of parts of that person.. Maybe even every part of that person that they know. But no one can hold an entire person in their mind at once and say, yeah, I love this person. You think of something about them... Their smile, the way they smell, the strange little words they make up, how much they care for people, how stubborn they are, the crazy thoughts they have... You think how great that was/is/will be about them. But anybody you know... First of all, there's more to them than you can ever fully know, no matter how much time you spend with them. And second, any person is too complex for you to fully hold who they are in your head at any given time.
Of course, sometimes, you just don't let yourself get to know someone. I don't know why this happens, but sometimes it does. You think you know them. But you ignore everything about them that doesn't support who you want to believe they are. Worse than this, sometimes you fall in love with who you want someone to be. Then things just get icky...