Jordan Peterson, the Canadian psychologist, paraphrases Carl Jung’s warning of psychedelic experiences saying “beware of unearned wisdom”. 

It is told of the great sage Rabbi Eliyahu of Vilna that he declined the opportunity to gain tremendous esoteric knowledge through the mystical experience of a maggid, an angel teacher, because he wanted his wisdom to be his own. Knowledge achieved through endeavour is something with which a person can cope, but unearned knowledge may pose a psychological and moral burden too great to bear. 

It is in this context that the Meshech Chochmah, Meir Simcha of Dvinsk (1843-1926), explains the prohibition of offering leaven or fruit honey. 
At the very beginning of the Torah, Cain and Abel both bring offerings to God. Cain brings of the fruit of the ground and Abel of the firstlings of his flocks. Yet God accepts Abel and his offering but rejects Cain. 

Why? The Meshech Chochmah notes the origins and source of the respective offerings: Cain offers that which is of the ground while Abel offers from his flock. Cain was offering ready-made fruit which he did not work for. All he had to do was pick it from the ground. Abel, on the other hand, had offered of his flock of domesticated animals which he had raised and looked after. Cain gave God what was already His, whereas Abel had offered God the fruits of his own labour. 

Following this logic, the Torah commands that any offering a human brings before God should be of himself. Domesticated animals, meal offerings and wine are all fruit of human labour. Most importantly, the finishing of the product is by mankind. 

Ripe fruit and leavened bread might have human involvement, but the completion of the product, be it the rising of the dough or the sweetness of the fruit, is done by God. There is no point in serving up to God His own sweetness if it was not acquired through the work of man.

The greatest service to God is not through human inactivity and passivity, but through human endeavour and progress.