- Sheldon makes a scientific breakthrough and then realizes he made a calculation error which led to his success. He goes from being proud of the accomplishment to wanting it to go away.

- Howard wants to celebrate when he met Bernadette by writing and performing a song for her. He gets his friends to agree to play the music and help sing. She ends up in quarantine due to a mishap at work. He brings the gang to where she's in quarantine and sings it to her.

- Howard's gesture gets the others thinking about romantic gestures. Penny tries to surprise Leonard with a first edition book he wanted, but it turned out he actually bought it when he mentioned it. Leonard then finds out that she kept mementos of their romance and he finds that romantic.

- When Amy dismisses Sheldon's achievement, he finds that romantic. Poor Amy is left to dream about Sheldon wanting to kiss her.