Felicity's face falls. It's clear Harrison is unhappy she's here. And worse, it's clear he was having a good time before she showed up. Felicity scrunches her face up into some weird distorted position. Outwardly it might appear as 'Felicity being Felicity' (read: weird and random), but it's not random at all. She's trying to mask her disappointment. It's like putting personal mail through a shredder -- you can hide important information by simply scrambling it up.

"Yeah, Viola," Felicity scoffs, "You got anyone else you can harass?"