Things that are "necessary to explaining reality" exist. To explain reality, we don't need to know if we like people. It's simply not necessary. We can do just fine answering questions like "Do I want to talk to her right now?" and "Do I want to learn more about her?" and "Do I want to spend time doing X with her?". So, liking *does not exist*.
However, there is something the notion does come in handy for. What if, instead of trying to explain the world, we want to *predict*. Then, it is useful. That's what "liking" really is -- an expectation to continue wanting [various things]. The various things including wanting to spend time together, wanting to fuck, etc