Things that made me say OMG when they happened:
OMG, I was right about the statue — it’s Taweret!
OMG, Jacob met Little Kate!
OMG, Jacob had something to do with Nadia’s death!
OMG, Sayid got shot in the stomach!
OMG Jacob is reading a book by Flannery O’Connor! (This is kind of a personal OMG, because Flannery O’Connor used to be one of my favorite writers, and a model when I was writing short stories)
OMG, Sun and Jin’s wedding vows were so sweet! (No OMG for Jacob being there and speaking Korean, because by this time, that was almost expected.)
OMG, I think Miles may have nailed it — the bomb will cause, not prevent, the “incident.”
OMG, the bomb didn’t go off.
OMG, Juliet fell down the hole! Noooooo!
OMG, Richard knows the answer to Ilana’s riddle.
OMG, Locke is in the box!
OMG, Michael Emerson is such a good actor! (“What about me?”)
OMG, Juliet is still alive!
OMG, the screen turns white.
OMG, How am I going to wait eight months for the next episode? OMG, OMG, OMG.