I have also been thinking about this lately. From what I have concluded is; When the process of accountability comes to an end on the Day of Judgment, on an individual level (talking about it from the perspective of those qualified for Jannah) each and every one of us will already be satisfied considering, first and foremost, how we witnessed the perfect justice of Allah by bringing out each and every action/thought/word of us and all the parties related to us. That will in and of itself be enough for us, in my opinion. But we will be given Jannah (his ultimate pleasure). As ‘ a reward for what we did in this life AND some more.’ This idea has also come at many places in the Quran “as a result of what you used to do and some more.” So everyone will already be having more than they deserved on top of when they know they have God’s pleasure with them (after which nothing else is really needed).

However, I still have a question a bit different than yours; Wouldn’t/Would we want to improve ourselves further even in Jannah? I mean, those in a lower degree want to reach the level of those on a higher level (based on faith and allah’s Radha) not the other pleasures.