Krishna is the Supreme Personality of Godhead and is fully realized by His pure devotees but everyone is realizing different aspects of Krishna according to their desires and their surrender to Krishna. In this way Krishna is the object of everyone’s realization and He reveals Himself according to one’s desire to have Him.In the transcendental world also Krishna reciprocates with His pure devotees just as the devotee wants Him.For them I am covered by My eternal creative potency ; and so the deluded world knows Me not, who am unborn and infallible.” (Bg.7.25) This whole material world is created by Krishna for us, the rebellious living entities who want to try to enjoy separately from Him. The devotees enjoyment comes from seeing Krishna happy.Actually there is no question of us ever being separate from Krishna but to create this illusion for the demons who want it Krishna has created that they think they can turn this material world into a happy place where they can live forever.So the summary is Krishna reveals Himself to the living entities in the way they want to see Him.He states here clearly that He gives remembrance and knowledge — but He also gives forgetfulness.
Krishna directly states that for the non-devotees — because they do not want to see Him — He does not manifest Himself before them: “I am never manifest to the foolish and unintelligent.
Even if you look at the greatest and most powerful men on the planet — they all have to render service.
If you take the President of the United States — a very big post — still he has to serve the country.
Also Krishna helps the impersonalists who desire to commit spiritual suicide by annihilating the individual existence of the living entity — Krishna helps them by absorbing them into His effulgence.
Because the impersonalists do not agree to accept the eternal, blissful Personality of Godhead they can not enjoy the bliss of personal service to the Lord, having extinguished their individuality.