Memories of Libby rush back to Hurley during their kiss on the beach, Desmond is watching

At the beach in the sideways, Hurley lays out the blanket and unpacks the picnic basket so he and Libby can finally have their date. Libby stares out at the ocean and when Hurley asks what's wrong, she says that nothing is wrong, but it feels "off." She says the picnic is "like a date we never had."

Much like on the island, Hurley questions why Libby would want to be with him. She says that she likes him, but he says that she's "delusional." She leans in and kisses him, and suddenly, memories of their time on the island rush back to Hurley (just like they did with Desmond).

Hurley is stunned for a moment and then says that he thinks he's remembering stuff. Libby asks "You mean I'm not crazy," and Hurley says that he doesn't think she is. Libby is overcome with joy.

As the shot gets wider, we pan down to see Desmond sitting in his car, watching the two of them. He has a sly smile on his face as he drives away.

So what will be the repercussions of the Oceanic 815 passengers remembering the original timeline and why is Desmond starting to push people towards these revelations? What does Desmond know right now that we don't?