Forms are an important part of the conversations we have with our customers
Web forms may not be the sexist thing to talk about in UX but they sure are important. They are a medium through which our customers can tell us what they want to do online; be that to register, order, sign up to something or simply provide feedback.
Done well, forms give customers a sense of control and allow them to get stuff done online. Well designed forms enhance customer trust and brand reputation. Done badly, the opposite is true and ill thought-out forms are a sure fire way to annoy customers and increase their general dislike in a brand.