I've worked in the TV news industry and the hours are so bad that I landed up making some of my best friends at work. After all who else would be off on the same day in the middle of the week as me? Who else understood the pressures of working in the media? So I was always hanging out with my colleagues.
The down side of that is that your personal and professional life is the same. In most offices people just work and don't really hang out with their colleagues outside office. Is that a good thing or a bad thing? Can there be genuine friendships made at work? Or are their too many insecurities among colleagues to actually result in friendship?