Also known as RBS, this is a condition of uncontrollable ridiculous happiness. The name originates from the ability of those who suffer from RBS to get happy and excited about anything, even a pile of bricks.
Guy #1 to Girl: What are you smiling about?
Girl keeps smiling.
Guy #1 to Girl: No, but really, what are you smiling about?
Girl keeps smiling happily.
Guy #1: WTF!
Guy #2 whispers to Guy #1: She's got Red Brick Syndrome...