"Oh, I dunno," she mutters, her temper flaring instantly as he fills the spot next to her without so much as a 'may I', "Maybe because you don't like me?"

There's not a lot she can do here save for storming away like a child, and she refuses to give him that satisfaction. Besides, he'd doubtlessly find her again anyway, and she's aware that people are still looking at them. Or, perhaps, just her, because Astarion seems to be currently using her height to block out each casual glance in turn, like he's seeking shelter from the sun. It's annoying. He's annoying, and Abby has no idea how to address him.

Maybe she should have wine to sip, too. It would at least be something to do with her hands, which are currently being held a little stiffly at her sides. "It's mutual, by the way. In case you hadn't noticed."