Maria is a single line, and it leans on one small word: "still." The speaker says they smile when they think of her, and that "still" quietly tells us something has changed. Time has passed, and whatever happened between them is over, or at least out of reach. Yet the smile hasn't gone away.
The speaker calls this "funny," but it doesn't sound like they're laughing. It sounds more like mild surprise, as if they expected the memory to hurt and found it didn't, or not only. There may be a bit of ache tucked underneath the warmth, though the poem never says so. Judging by the wording, we can't tell whether Maria left, whether they parted on good terms, or whether she simply drifted out of the speaker's life.
The lowercase letters and casual phrasing make it feel like a private thought, half-said aloud. The mood is gentle, wistful and quietly affectionate, and the brevity leaves the reader to fill in the rest.