Yoni, if I told you that at the end of a thick forest there was a treasure buried that no one knows about, but you have to go through the dark, thorny, cold forest for a few days to get there, would you be upset at me? No! You'd plow through the forest with joy, knowing what awaits you at the end!
So why are you so upset at G-d? Do you believe that there's a treasure awaiting you at the end? If you do, accept the pains of Yiddishkeit with joy!
And if you'll ask, but WHY did he make a forest in the first place? That we can't answer. But just as you wouldn't be upset at me if I revealed the secret of the hidden treasure to you, in spite of the difficult journey across the forest, so too, you should accept the pains of the journey to the next world - the palace - with joy!
It all boils down to Emunah and priorities. If you truly believed, you would be the happiest man on earth. And if you don't believe enough, that's not G-d's fault, is it?