The main purpose of conversation between Gregory and Samson was to describe the servants as being ridiculous and being just boys, while talking of fighting against the Montague.
Explanation:
Solution
The tone of their conversation between both of them was that Sampson began the conversation so that he can defend his sword fighting abilities and bravery This becomes apparent when Gregory abused Sampson's capacity, by saying that he is not " moved swiftly to strike his sword" and went on saying that Sampson is only moved to run away.
However, the main purpose of the whole communication between Sampson and Gregory is to depicts the servants as being being boys, ridiculous, and talking about fighting against the Montague.
