I definitely think Clare kissing Eli was the culmination of letting out suppressed feelings she’d been holding in all year. Clare basically admitted that she’d been keeping her distance from him all this time for his own sake more so than her’s, which confirms to me what I’ve always suspected. Clare broke up with Eli because she thought it was the right thing to do for him. It was not because she didn’t love him anymore. Those feelings never really went away, which is why the moment they reverted back to their former flirty bantery dynamic from TBP, it was so easy to just go up and kiss him like the past year hadn’t even happened. All the feelings came rushing back. I think that kiss brought about a revelation of sorts for her. She might have initially kissed him to test the waters to see if there was still something there at all, but afterwards.. there’s no doubt she’s realized she still loves him, and will probably always love him. I’m confident that this second time around, Eli and Clare will have a stronger relationship than they did before.