From Ohr Avigdor Shaar Habitachon by Rabbi Avigdor Miller
When we speak about the World to Come, it’s not possible to specify what the reward is, but one thing we do know: that the people who gain Hashem’s favor will attain a closeness to Him and that closeness will be the greatest form of happiness.
As it says in the Gemara (Brachos 17a), tzaddikim (the righteous) don’t eat or drink in the World to Come. They sit with their crowns upon their heads and enjoy gazing upon the splendor of the Shechinah. This is something entirely different from any concept we are familiar with in This World.
The Rambam says (Hilchos Teshuva) that even Moshe Rabbeinu couldn’t understand it while he was alive, and if it were told to him he would not have been capable of explaining it to others. It is like trying to explain colors to a person who was born blind; to him, colors are meaningless.
So we are not at all capable of understanding what is meant by the happiness or the pleasures of the World to Come, and we have no hope of grasping this concept in our lifetime. But all we have to know is that there is a spiritual reward. Hashem provides that reward and He knows what is necessary to make our neshamos (spiritual selves) supremely happy.