[greggarious]

>Is making your co-workers your friend group a new thing?

Friend is a strong word. You might go out to a bar with your coworkers, watch movies, game, attend birthdays. But it's a superficial "friendship". You don't talk about anything deep - that would be a "bummer".

[geggam]

The less your co workers know about you the less they have to use against you when its dog eat dog time.

[greggarious]

Agreed, but I find it draining to have to attend a bunch of social events that are "work" (in the sense you can't be your authentic self) which in turn leave less time for a personal life.