From Al- Hasan who reported : Abu Dardaa (radhiyaAllaahu anhu) used to say :

من يتبع نفسه كل ما يرى في الناس يطل حزنه ولا يشف غيظه

 “The one who’s soul follows [desires] all that which he sees possessed by the people :  he just increases his sadness, and will never satisfy his cravings.”

Source :  Zuhd of Imaam Ahmad : 779