I want the perfect muffin, or nuffin

Why can't I bake muffins? I've tried several times. They don't turn out light and fluffy, and poking over the top of the muffin case. They turn out a bit hard and a bit dry, and barely reaching the top of the muffin case. I don't do any super-healthy wholemeal recipe. In fact I've probably tried several recipes over the past few years. I don't think I can be a proper American mom until I can bake muffins (and yes, I do already make a mean apple pie).

Let's have a poll. I'm relying on you, Bloggy Friends. Don't let me down. I can't accept I have no future in muffins. You can select as many answers as you like, and/or leave me a comment with further information.