The fact that she heard her semi-estranged friend speaking to her or that her mouth went from being filled with the bitter taste of the beer to the sweet taste of chocolate milk. Those were both very unexpected events.
She then heard her speak of 'her Willow' Swell an alternate reality. Not exactly something Faith looked forward to, but hey occupational hazard.
Once she put down her drink, she noticed food. Burger and fries. She has not had this for months. When she did try to have a burger in Europe, it tasted differently from American burgers. This burger clearly looked and even smelled American. She put down her bee...or rather chocolate milk and she picked up the burger and took her first bite.
Once she chewed and swallowed her bite, she looked to Buffy. Faith would appear to look a bit worn out from years of saving the world, slaying, and her cigarettes she smoked since she was in prison.
"I retired from being an active slayer. Kinda worn me out. And save your lectures and giving me the whole 'How could you leave your calling?' speeches to yourself. I've heard it all from B.........err my B." She hated alternate realities. They always confused her.
She then took a french fry in her mouth and chewed it and then swallowed. "So how have you been?"