I have certain default things I say out loud when I’m alone. “I’m tired” is one. I’m not usually tired when I say it.
“Fuck you” is another. This I say when I remember having hurt someone. I say it sharply, like a command to a barking dog.
“I love you, sweetie” is another. I say this when I wake in the night. If I’m addressing anyone, it’s K, but usually I’m just saying it.