She paused a little when she realized he was smiling. He looked good smiling. It made him look a bit cuter. She almost wanted to keep it that way, but he would probably go back to being straight-faced all over again. She had to stop herself before she started having a crush on him. There was no use in falling for someone she was 90% sure was at least interested in someone else. 

She raised her eyebrows back at him when he teased her back, starting to laugh again. "Hey, at least I can use my height to my advantage! I can give in depth check ups while you're still waiting for your microscope to be tall enough for you!" Anna countered. He seemed very...serious, but at least he didn't turn up his nose from a little humor.