The speaker is caught in a painful pull toward someone who keeps slipping away. The two are supposed to be "just friends," but the poem suggests there are feelings neither has said aloud, only hinted at in late-night phone calls. The speaker admits to a strange contradiction: wanting to push this person away and hold them close at once.
The imagery of the desert carries much of the feeling. The speaker longs to be the "lone desert flower" that makes the other person smile, and later calls the loved one a tumbleweed, something that drifts in and never settles. The counting of words, one to greet, two to ask how they are, three to say what was once felt, shows how much a tiny gesture matters.
The mood is wistful and tender, with an ache underneath. By the end, the speaker accepts the losing, as long as the person keeps coming back. That acceptance feels both devoted and a little sad.