happiness是不可数名词。
happiness：n.幸福；愉快；(用语等的)适当；幸运；
happy：adj.感到(或显得)快乐的；高兴的；给予(或带来)快乐的
相关介绍
Money is not essential to happiness.
金钱对于幸福并非必不可少。
The book describes a spiritual journey from despair to happiness.
这本书描述了从绝望到高兴的心理变化过程。
Career success is no guarantee of happiness.
事业成功并不是幸福的保证。
