Desmond...why do you have memory loss?

I swear the last Lost episode was fluff. I mean what does Desmond having some strange memory loss have anything to do with the over all story? It was touching that he was able to finally tell Penny he loved her but can we get back to John Locke and Jacob the creepy ghost or Jack and Kate in the future? And is it me or is Sawyer...I mean James getting annoying with all the wise cracks. This is a guy who in season 1 shot a charging polar bear with a hand gun. I say "bring back the old Sawyer!"