Chazal tell us "Oy Lani MiYom HaDin, Oy Lanu MiYom HaTochacha", woe is to us from the day of punishment, woe is to us from the day of rebuke. Isn't this backwards, since rebuke comes before punishment?
Rav Chatzkel Levenstein explains that the thing preventing us from seeing the real truth is our own bias and self interest. It is impossible to be totally honest when the truth will harm you. That being the case, even when facing Hashem in the Olam HaEmes we will not see the real truth because we know that punishment awaits us. We will remain biased until after we have already paid the price. Because of this bias the Tochacha will not penetrate our hearts.
Only after we have already received our punishment and there is no longer any self interest in denial, only then will we clearly see the error of our ways. Then the Tochacha will be self evident. Moreover the pain of the honest tochacha that we feel will be far greater than the Din or the punishment given by Hashem. In the world of truth, living with our past misdeeds is the worst punishment imaginable.
When we get to Shamayim first we will go through a cleansing process of din or punishment, Oy Lani MiYom HaDin. After that we will face something far worse than that, Oy Lanu MiYom HaTochacha. Only then will receive the far greater punishment of facing and living a bitter reality of our past sins.