Acceptance of dua is a great favor from the Almighty Allah. So, it’s only logical for us to thank Him for his blessings and bounties. Unfortunately it is common for many of us to forget the time, when we were desperately calling on Allah for His help, and get so carried away with enjoying the results, that we forget remembering Allah and thanking Him for His grace.
Allah says in the Quran:
“He it is Who enables you to travel through land and sea, till when you are in the ships, and they sail with them with a favorable wind, and they are glad therein, then comes a stormy wind and the waves come to them from all sides, and they think that they are encircled therein. Then they invoke Allah, making their faith pure for Him alone, (saying): “If You (Allah) deliver us from this, we shall truly, be of the grateful.”
But when He delivers them, behold! They rebel (disobey Allah) in the earth wrongfully. O mankind! Your rebellion (disobedience to Allah) is only against your own selves, — a brief enjoyment of this worldly life, then (in the end) unto Us is your return, and We shall inform you of that which you used to do”
Quran (Surah Yonus, Verses 22,23)
Shaykh Ibn Al-Sa’di (RH) said in his interpretation of the above:
They understood that they were doomed, so they ended their dependence on created beings and they realized that no one could save them from this hardship except Allah alone, so they called upon Him, making their faith pure for Him alone and promising that they would adhere to that, and they said: “If You (Allah) deliver us from this, we shall truly, be of the grateful” but “when He delivers them, behold! They rebel (disobey Allah) in the earth wrongfully” i.e., they forget that hardship and that dua, and what they committed themselves to, and they associate others with Allah whom they acknowledge cannot save them from hardships or protect them from difficulty. Why are they not sincere towards Allah in worship in times of ease as they are at times of hardship?
But they will face the consequences of their rebellion, hence Allah says: “Your rebellion (disobedience to Allah) is only against your ownselves, — a brief enjoyment of this worldly life” i.e., everything that you hope when you rebel and turn away from Allah, is to make some worldly gains, which will soon come to an end, then you will leave them behind: “then (in the end) unto Us is your return” on the Day of Resurrection, “and We shall inform you of that which you used to do”. This is the ultimate warning to them against persisting in what they are doing.
[Tafseer Al-Sa’di, 361]
The essence of the above is that while we tend to return to Allah when we are in tough situations, we forget Him and disobey Him when life becomes easy. Let us not forget that both good times and bad times are a test from Allah. If we fail that test (by disobeying Him in good times, for example), we may not get a respite next time when we are faced with tough times again.