Mock Town is a port inhabited mostly by pirates, despite it looking like a resort.
Pirates who dwell here tend judge their level of skill and power based on their assigned bounties, meaning those carrying bounties above average (10-20 Million Berries) are often respected more by the citizens. The town itself is built on the money that the pirates spend inside it freely. For that reason alone, though fighting does occur in the town, the pirates rarely attack the people living there.As stated by the bar tender at the pub Nami, Zoro and Luffy states, a normal person would say they hate the town, but there are not many normal people there. 
One must leave within the 4 days of the log post resetting to avoid any serious trouble.
The most famous mentioning of Mock Town comes from Jon Wahl's ship log book, who mentioned the "Town of Mockery".
Roshio is killed by Bellamy in the town when the storyline first reveals the town of mockery. Later, the Straw Hats arrive trying to find information on Sky Island. Luffy, Zoro and Nami head off to find information, however end up at a pub where Bellamy attempts to pick a fight with them. After Bellamy humilates the trio because they refused to fighthim back, the three leave.