The sentence seems irrelevant because it lacks detail and focus. But by adding more explanation we can easily add to its relevance : Laura wants to stop the party, but Mrs Sheridan gives her a new hat and Laura is seduced by her own beautiful image ; egotistically, she forgets about the accident and conforms to the selfish standards of her family. Now the hat helps the essay to achieve its aims.
Sometimes irrelevant material can be made relevant by explaining more and adding greater detail. Here is another sentence from the same essay : Laura wants to stop the party but Mrs Sheridan gives her a new hat.
Relevance of Philosophy Essay - 3620 Words