In just three short lines, the speaker says something plain and heavy: depression is the feeling they know best. They don't describe it as a visitor or a storm. They call it "familiar," the way you might talk about a street you've walked down a thousand times or a person you've known for years.
That word is what gives the poem its weight. Familiarity usually suggests comfort, but here it hints at something more tiring. Depression isn't a rare event for this speaker; it's the emotional default, the one they recognize before any other. The dash after the opening word makes us pause, as if the speaker is naming it and then taking a breath before admitting how well they know it.
The mood is quiet, flat, and a little worn down. There's no drama or self-pity, just a calm statement. The short lines and the empty space around them add to that feeling, leaving the reader alone with the admission. It's sad, but also honest, and that honesty may be what stays with you.