Remember that teenagers are basically insane, by a mature adult's standards. Their brains are still undeveloped (MR scans have shown this to be true); they cannot distinguish the shades of grey a mature adult brain can. Everything is black and white to them (hence the youthful idealism yearned for by the old and compromising). They are also extremely self-centered because their ego is developing by leaps and bounds at this time; they are trying to develop a sense of themselves separate from what they were--your child. You can't help but remind them of what they were... a dependent drooling mini-you who needed their nappies changed and woke up crying/puking/peeing/pooping in their cribs every night. They are kind of subconsciously resentful of the fact you know their weaknesses that way and that maybe you might have trouble seeing their new strengths. Throw the raging hormones into the mix and you can see why it's a miracle they have anything civil to say to you at all. All part of being that wonderful freak-of-nature called a teenager. They treat their familes like dirt and are usually polite and helpful to their friend's families.

Just remember you were as big a headache to your parents too. It wasn't your fault and it isn't theirs now. It's the parent's for giving birth to them. ;)

They'll probably come around much later, but in the meantime you've got some bitchy years ahead. I forget who said it, but there's a quote that made me laugh and nod: "When I was 16, I thought my father was the biggest idiot on the planet; by the time I was 24, I was amazed at how wise he'd become."