Gratefulness

 

 Surah Ibrahim(14) verse 7.

And remember when your Lord proclaimed: "If you give thanks, I will give you more. But if you are thankless, verily My Punisment is severe!"

Notice the opposite of the word 'syukr(syakartum)' is 'kufr(kafartum)' which in this context means ingratitude, but is usually used to mean disbelief. So being ungrateful borders disbelief. May Allah save us from being thankless servants. Thus the prophet advised Muadh ibn Jabal:

“O Mu’aadh, by Allah indeed I love you, and I advise you, O Mu’aadh, do not forget at the end of every prayer to say:
Allaahumma a’inni ‘ala dhikrika wa shukrika wa husni ‘ibaaditika
O Allah, help me to remember You, give thanks to You and worship You in the best way).”

[Narrated by Ahmad, Abu Dawood, al-Nasaa’i, and others; it is saheeh]