Congratulations! And I *totally* get this sentiment. I was trying to explain to my oldest friend (who has a delightful and easy 6 mo singleton) that if I heard a good friend was having twins, I'd actually be a little sad for her... and I think she saw I was a horrible person. But I am just now starting to get into a groove with my twins and older son, and I do think those first months (well, first 15 months for me), when they have sooooo many needs, well, they just don't and can't get as much from their mama and daddy as a singleton. The last few months have started to be fun, though, and our life is already so much richer for all of our kids, including our twins, but I still don't know that I'd wish twins on anyone...yet?
So -- I am very happy to hear you are having JUST one.