When someone is not paying attention.
It's like talking to a brick wall. Are my words falling on deaf ears?
When someone just goes on and on, never getting to the point, we Brits refer that to: "Rabbiting on."
"For goodness sake, shut up and cut to the chase. will you."
And to shut them up use an idiom in insult form: "For heaven's sake, you're giving my arse (ass) a headache!"
At the other end of the spectrum the one who is at a complete loss for words: "Has the cat got your tongue?"
Have you ever seen someone with no interest in appearance, looking very scruffy or dishevelled? A classic idiom describing that is:
Looking like they’ve been dragged through a bush backwards. Or following the feline theme. Looking like something that the cat dragged in.