Yes, I know, this is not a book review but please bear with me whilst I ramble.
As some of you may or may not know, lately I have been reading the Scarlet Pimpernel series. What I thought was just one book turned out to be a whole collection of them and wow was I chuffed! There is a part of me that absolutely loves the simple, swashbuckling, good triumphing over evil storylines that are so prevalent in these books and I just can't get enough.
This series, along with others like it (Sharpe, for instance) follows the very basic plotline that has survived for so long: problem is mentioned, good guy vows to fix it, bad guy finds out about it, good vs evil, goodie wins (sometimes in smart way) and baddie looks incompetent to his superiors - makes me smile everytime!
However, despite this predictability, there is always a point in the book where the badguy has the upper hand and I put my book down for fear of him winning (yes, I know there are more in the series, but I conveniently forget every time). This is what does it for me - a book that can make you really get into it and invest your own emotions into it to the point that you cut yourself off from the practical side of your mind and start hoping that he'll be okay - despite what experience has taught you.
The Scarlet Pimpernel & Sharpe are especially guilty of this - every single time I read one of the books I stop halfway through thinking 'Oh my gosh, what if they kill him!' - yes, even during the second book in the Sharpe series :S - and so have to put it down and make my way back to reality.
I guess my point is that these books, especially Sharpe, are often scoffed at as 'easy reads' whilst having this fact overlooked or labelled as predictable. Yes, from an outside view point or if you read them all in one go, they are predictable - but take them slowly, read them separately and you may see what I mean.
Baroness Orczy did it with Sir Percy Blakeney vs Chauvelin & Robespierre and Cornwell with Sharpe vs Hakeswill - the classic good vs bad is not such a terrible, simple storyline :D