The passage of the soul to the next world involves the crisis of forgetting.
There is usually a transition period to enable a development of higher awareness to take place, just as people who move to foreign countries need time because they continue to see things with the eyes of their own past culture.
All of which, incidentally, is one of the reasons for the saying that there are several things that can be obtained only by suffering, among them being the Land of Israel (also Torah and the next world).
Because these things are of the nature of another realm of being, a better world, that require a certain process of eliminating the previous world.
This may also be the meaning of the endless struggle of tzadikim, who move up from one stage to another and have to keep discarding familiar sources of satisfaction and of joy in order to achieve ever-higher levels of experience.
This points to an endless elevation of values and levels of happiness.
But our capacity to experience them is limited.
We are confined to a certain limited scale of response.
Beyond a particular extreme, we cannot appreciate what is happening.
Just as our vision reacts only to certain wavelengths of light, so that we cannot see the infrared, the ultraviolet, or the x-rays, thus, too, for the most part, we do not enjoy the radiance of the Shekhinah, the source of all delight.
In order to do so we have to reach an equal, or similar, quality of light in ourselves, going through a process of soul purification both in this world and in the next.
–Rabbi Adin Steinsaltz
From The Candle of God by Rabbi Adin Steinsaltz