Three plain lines of rejection, then one question that undoes them. That is the whole shape of this short poem. The speaker lists what they know to be true: the other person never wanted them, never cared, never loved them. The repeated "I know you never" sounds like someone reciting evidence, trying to talk themselves out of a feeling.
But the last line breaks the pattern. "Why do I miss you like I do?" admits that knowing the facts hasn't helped. The speaker's head and heart disagree, and the heart is winning, even though it makes no sense.
The mood is quiet, raw, and a little bewildered. There's no anger here, and no dramatic language. The simple wording makes the hurt feel honest, like something said out loud late at night. The poem doesn't offer an answer to its question. It leaves us with the ache of missing someone who, by the speaker's own account, never gave them reason to.