When some trouble touches man, he cries to his Lord,turning to Him in repentance: but when He bestows a favour upon him as from Himself, (man) forgets what he cried and prayed for before, and sets up partners to Allah, thus misleading others from Allah's Path. Say, "Enjoy your blasphemy for a little while: verily you are (one) of the Companions of the Fire!"39:8
[Lessons from this verse] We normally reserve turning in repentance to when troubled times come upon us. No, we are equally commanded to turn in repentance when the mercy of Allah is showered upon us, because that is the time so many people attribute that mercy to other then Allah.