just because she can

媽: 我煲了蠔鼓瘦肉粥, 你話我好唔好加兩個節瓜落去?

女: (喝止) 唔好!!! (兩秒後) 點解你會想落節瓜?!

媽: 因為有(兩個節瓜)囉.