Do you think it's important to be friends with your co-worke

I don't think it is important.
There is two ponits to support my choice.The first,being friends with my co-worker will affect my some ordinary behaviour in corp.and make me slid into messing the business affairs with personal affairs;The second,being friends with my co-worker may make me value the benefit of my company less than the benefit of my friend,so as to affect my decision.