what should you do when someone says or posts something which has no relevance to you, your life or your reality

what that someone said or posted has no 'relation' at all to your life, you, your reality etc, whether it's a word or words that person used or a comment they posted, all of which have zero relevance to you or your reality, but that person seems to think it is relevant to you? then you think 'why' do they think that?

i've been in a few situations like that with people online and offline, i'm quite sensitive, so have instantly felt annoyed when this happened with someone..

but what's the best reaction to that situation??