没心没肺活得不累
[méi xīn méi fèi huó dé bù lĕi]
The term 'no heart, no lungs' is an exaggerated way to express a person without sentimentality. People who are carefree and untroubled by emotions may not feel the pressure or troubles as they just don't let those get into their mind which makes for an easygoing life.