The Quran repeatedly notes, in more than one place, that few of God's servants are truly grateful, a recurring observation exegetes read as a deliberate corrective against complacency, since it implies gratitude is not the automatic response most people give to blessing but a discipline most people fail to sustain even while enjoying its objects. Ghazali connects this rarity to shukr's cognitive demand: true gratitude requires actively recognising a blessing as a blessing and tracing it to its source, an act of attention many people simply do not perform for the countless ordinary goods, health, safety, sight, that arrive too continuously and too unremarkably to prompt the reflection more dramatic gifts occasion.
The virtue's counterpart failing, kufr in one of its Quranic senses, means literally to cover over or conceal, and classical commentary notes the same root gives the word its more familiar theological sense of disbelief, an etymological link Islamic scholars have long used to argue that ingratitude and disbelief share a structural kinship, both consisting in covering over or failing to acknowledge what is, in fact, plainly present and given. Ghazali also warns against a subtler failure alongside outright ingratitude, gratitude expressed only in words while the blessing itself is put to no good use, treating verbal thanks without the corresponding right conduct of the limbs as an incomplete shukr rather than its absence outright, since the fullest form of the virtue, on his threefold account, requires all three registers, heart, tongue and deed, acting together rather than any one of them substituting for the others.