Fruit for fruit

Genesis 4:3

And in process of time it came to pass, that Cain brought of the fruit of the ground an offering unto the LORD.

Why motivated Cain to bring an offering of the fruit of his land to God?

Many answers could be given, but in the dozens of Bibliodramas I have done with this story, one intriguing suggestion pops up quite frequently: Cain had heard all about the wonderful Garden of Eden in which his parents started their lives, standing in stark contrast with the laborious, demanding life they were now living. He wished to get back to that Garden; he wished to get back into God's graces. 

So he reasoned: God became upset when my mother took a fruit. I will give back fruit. 

This has logic. Yet he is not successful - God ends up accepting Abel's offering and rejecting that of Cain. Again, many explanations for this may be offered. But perhaps one message emerging from this is that you cannot fix things simply by reversing them. If you have hurt someone with offensive words, you cannot simply say to them the opposite or "I didn't mean it" or "I was joking". Rather, a process of apology and genuine conciliation, and a true process of repentance, must take place.

This was Cain's mistake. He ought to have tried to rectify the root cause of his parents' sin inside himself. Instead, he thought a technical action would do the trick.

Abel, on the other hand, brought the choicest of his flock. In this he was putting God above his own desires; and this, perhaps, was a (partway?) rectification of Eve's sin in priveleging her desires above God. Hence, his was accepted.