I do find them a bit bleurgh & the reactions do seem a tad OTT, however when I think about it, if I was away from my kids for 3 weeks with absolutely no contact, not even a text, I think I'd probably get a bit emotional if I received a letter from them.
And when you think about, in every series when the letters arrive, the majority of the celebs do tend to get upset so who knows how you'd be in a similar position.