When you work with people day after day, you’re bound to make friends. If handled correctly friendships can make work so much more enjoyable, or at least tolerable if you’re in a less than desirable job, but there can also be some pitfalls if you’re not careful.
Some of these friendships in the office will outlive the job; others will not. In either case, office friendships are a valuable part of any professional network and can be a boost to your career if managed in a professional manner. If mishandled they can do a tremendous amount of damage.