Why do people feel the need to talk about their personal life at work?

I work as a server, and some of the girls talk freely---like how many people they had sex with or that they got intoxicated the night before, etc. I personally like to keep things to myself because I know once you open your mouth, everyone knows by the end of the night. Why do people feel the need to talk about their personal life at work?
No clue. They should be more professional and do what they are paid to do.Why do people feel the need to talk about their personal life at work?
I guess they feel they need to tell people. Its totally fine to keep things to yourself :)
The only friends they have are the people at work.
cuz a personal life is way more interesting and makes far better stories than talking about work
cause they can still have friends at work, and u might as well talk to them there. or they don't care if everyone know by the end of the night. or they're just really bored and want to talk. some people like talking about their personal lives.
maybe they need to clear their conscience or they don't have anybody else who swill listen to that nonsense.
suck it
Their obviously comfortable with their work environment to be able to discuss things of an intimate nature. But your absolutely correct that it's best to keep certain things private. This is especially true if you want to respect a good friend or partner.