I'm actually convinced that ASSa tells Isaiah to act up tickle and annoy Abbie. So it looks like she's happy and excited, because otherwise she just chilling out. When she not being bothered she's pretty quiet unless she wants something. So when they want to get her hyped up, they chase her, they tickle her and wrestle her, leg humphers think that she's enjoying herself and in it reality she's just getting hyper. Not that she's getting excited for anything.