Hazrat Moulana Ashraf Ali Thanwi (rahmatullahi ‘alaih) once mentioned:
So long as a person regards himself unworthy of the favours he enjoys and recognizes the favours to be a sheer grace and bounty from the side of Allah Ta‘ala upon him, he will continue to receive from the favours of Allah Ta‘ala and he will not be deprived of the Divine Grace. However, as soon as he regards himself to be deserving of the favours of Allah Ta‘ala, then this will be regarded as ingratitude and ungratefulness. When one falls into ingratitude, the favours that he is enjoying will be snatched away from him. The outcome of ingratitude is extremely serious. (Malfoozaat Hakeemul Ummat 5/332)
Source: Ihyaauddeen.co.za