What do we learn about the town and what is happening there

Very early we discover a feud between the Montagues and the Capulets.  We see the servants "teasing" one another - "I will bite my thumb" - which was a way of flipping someone off and being insulting.  Then Tybalt comes in, he of the fiery temper, and just helps to escalate the conflict into an all out swordfight and brawl.