How do you deal with nosy relatives who judge you underneath the smiles?

It's sad that there are so-called relatives who are like this. I just smile back; the kind of smile that says I'm the happiest person on earth. Like there's nothing wrong with my life and I'm simply happy with everything. Either they will get tired of judging me or seeing me enjoying a 'perfect, happy life' will kill them. lol Do not allow them to get on your nerves. Most probably, they are just jealous. Don't stress yourself on people like them. I'd like to quote Justin Timberlake on his Innovation Award Acceptance speech last year, he said 'your critics do not count. Their words will fade. You won't'. If you can try to look it up on Youtube, it's very inspiring. Sorry I can't post the link.