Why did the old lady next door talk about me and look like that at me?

What she means is that you don’t know the inside story. In fact, their family is rich but you don’t know. What he means by laughing is that they hide everything from you and laugh at you for not treating you as one of their own. , in fact, you don’t need to care, after all, it is other people’s business. You said it doesn’t matter, just laugh it off and it will be fine.