Although this question is opinionated, I believe that a government is absolutely mandatory to have a successful society. You simply cannot count on your citizens to agree on everything and all obey laws. It is human nature to want something for nothing, which is what laws are in place to prevent. You also would not have any form of protection such as a military, which means your society would get taken over by someone wot ha government very, very quickly. To put it short, yes, a government is 100% required.
