Excuse - Justification for why something didn't happen the way it was assumed or intended to
Reason - The convincing or prevailing thought that precludes a conclusion
I could tell you the reason why that lazy farmer made that excuse that he didnt have enough gas as to why he didnt complete his deliveries.
Because hes lazy. His excuse didnt hold weight as there were gas cans filled with fuel in the polebarn.
His reasoning justified his excuse to not finish his job.
But theres no excuse for his reasoning. Because his prevailing thought was not conducive to the task set for him, nor was it true that there was no fuel.
An excuse deviates from the set norm or expected path.
Reasoning is the basis or foundation that creates an excuse to not do something OR taking action to do something.
I'm reading this over and I apologize in advance for the confusion lmao.