Co-workers

Do you think it matters or not if your friends with your co-workers or not? Will it benefit you? Well in my opinion I think that you don't need to be friends. Like the famous saying goes "don't mix pleasure with business" I think of the same with having friends while you work. Also it may be good to interact with co-workers and if you become good friends then its good but I don't think that you need to have friends at work. You go to work not to play around>