How is it "not nice"? The problem with pre-announcing products is that it kills sales of your existing products.
A lot of manufacturers don't pre-announce their products. It just so happens to be the case that Apple's users are more passionate than the users of the average brand, so they tend to get in a tizzy about not knowing, the wait, and the hype.
I hate to be rude, but the problem isn't Apple. It's the users. There's really nothing to be angry about here. If the waiting game is too stressful, then maybe you should pick up a current model, or find ways to manage that stress.
TOTALLY AGREE! It's not their problem though it does not change the fact that they piss many of their customers as you can see here. But you are right, they do not torture me to wait or buy their products...