Why do we listen to sad music when we're sad?

We all have had a shitty day when we feel horrible and nothing goes right, and in some way, we end up listening to sad music. We're sad, why listen to sad music? To feel even sadder? I saw a video in which the person was wondering that, and, also a friend asked me why I listen to sad music when I'm sad. So, I started wondering about the reason and asking myself why we all do that. And, I have an answer, which is why I think we do that.

I don't think we listen to sad music when we're sad to feel even worse. But, in contrast, I think we do it because in some manner it makes us feel better (maybe it doesn't, I don't know about you all). Why does it makes us feel better? I'm giving you an example to make you understand what I'm trying to say. When you're going through something, whatever it is, it usually makes you feel better when someone comes and tell you: "hey, I went through the same", "I know what it feels like", or "I understand you". Doesn't that make you feel better? Maybe it doesn't make you feel better, but it makes you feel like you're not alone. And, that little thing can even make all easier, feeling like you're not alone. 

I think that that's what happens with music, specially with sad music. At least that's what happens to me personally. Even when the people who're playing the song are miles away and don't even know you exist, they still make you feel like you're not alone, and, sometimes, that's all someone needs, someone to tell them they're  not alone. And, the best part of it, is that you don't have to tell music your problems, you just have to find the accurate song to your problems, and I'm 100% sure there's one for yours.