Romance: the proof is in the reading

Writing a romance should be easy.  You take a man and a woman, throw in a few complications, shake it about a bit et voila!  Only I don't think it works like that.

I've read books that have made me swoon.  I've read a fair few more that have led me to consider lobbying for book-throwing to be considered an Olympic sport.  In almost every case, the problem was the same.  The protagonists were annoying.  In the far off days when I made a point of finishing every book I started, Wuthering Heights nearly brought on apoplexy.  Now I recognise that it is regarded as a classic, but Cathy and Heathcliffe irritated me beyond endurance (I was nineteen at the time, an age when I would have expected star-crossed lovers to appeal).  On the other hand, I've rooted all the way through an Alistair MacLean thriller for the hero to get the girl and had my heartstrings well and truly yanked when she didn't make it to the final page in one piece.

So is it just a matter of taste in the reader or is there something more to it?  What makes one pairing iconic and another moronic?

Anybody want to share their favourite couples here?