I learned some new Chinese last night (it's amazing that I can actually learn something from my wife). I mentioned seeing a lot of third wheels on Valentine's Day. Jia didn't understand that phrase and I had to explain it. She told me in Chinese it's 电灯泡 (dian(4) deng(1) pao(4)), or light bulb. I thought about for a minute to wonder why they'd use this, and I realized it was a very amusing way to describe the situation. No matter where the lovers go, the light is always on because of the 电灯泡.