小时候幸福很简单长大了幸福很复杂
[xiăo shí hòu xìng fú hĕn jiăn dān zhăng dà le xìng fú hĕn fù zá]
'Happiness was simple when I was young, but it has become complex as I've grown up.' This indicates a nostalgia of simpler times when happiness can be easily attained contrasted against the present day where joy might require complicated circumstances or efforts.