This is an important question asked by the people of jannah to the people of hell (Saqar), in Soorah Al-Mudaththir, verse 42. And very amazing, the people of Saqar can answer that question. Allah mentions it in the following 5 verses:
(43) They will say, “We were not of those who prayed,
(44) Nor did we used to feed the poor.
(45) And we used to enter into vain discourse with those who engaged [in it],