Like so many of us, Dan Estabrook never even saw it coming. It was a normal day at work when his office manager called him into her office for a normal-sounding meeting — until she unloaded a not-so-normal nugget of information.

“I wanted to let you know,” she said, “I’ve taken a live-in lover.”

Cue the awkward silence: Estabrook found himself victim of an overshare.

Blurting out too much information, or TMI, is something we’re becoming more and more comfortable with, some psychologists say. We obsess over the mundane details of celebrities’ lives and are eager to tell our own stories on blogs and Flickr accounts. And often, all that online openness seeps into everyday conversations.

Blame it on narcissism
One psychologist blames the influx of the overshare on an increase in individualism — and with that comes a hike in narcissism. We’re oversharing more now because we’re pretty pleased with ourselves, says Jean Twenge, a professor of psychology at San Diego State University.

“We just assume they’re going to be interested because it’s about me. Of course it’s interesting!” says Twenge, who is currently working on a book about narcissism among teens and twentysomethings.

But Leslie Reisner, a clinical psychologist in Los Angeles, is encouraged by all the sharing going on. Calling it narcissism is too negative, she says.

“There’s something healthy about sharing,” Reisner says. “It means they know it’s OK to show vulnerability.”

Spilling personal details can be a sign of self-confidence, Reisner believes, and 32-year-old Todd Enoch agrees.

“When I was younger, I was much more reserved,” says Enoch, who lives in Denton, Texas.  “As I’ve gotten older, I’ve broken out of my shell. Now I can share more with people.”

And sometimes, Enoch admits, he ventures into overshare territory. He remembers a scene at work when his co-workers were discussing how happy they were that the T-shirts for an upcoming promotional activity weren’t white.

“I don’t like wearing white things either,” Enoch chimed in, and then blurted out, “I just sweat at the drop of the hat!”

Breaking the ice
After a statement like that, consider the ice broken. A well-timed overshare can let others know it’s OK to let their guards down, and it can be a speedy way to make a connection with someone, Twenge explains.

“You realize you’re not alone,” Twenge says. “Previously, you might have thought, ‘Am I the only one with this problem?’”

But some say that’s looking at a relationship in a very backward way.

“People that are oversharing may be hoping for a connection with other people,” says Julie Albright, a sociology professor at the University of Southern California. Some people with TMI tendencies may be attempting to take a kind of relationship shortcut, going through the motions of an intimate friendship when there isn’t yet one.

That’s what happened to 29-year-old Becca Johnson during a girls’ night out. Johnson was talking to a friend of a friend whom she’d just met when the woman blurted out that she was having an affair with a former employee.

“In a way, it’s sad because you know they probably don’t have people in their lives to share things with,” says Johnson, who lives in Boston. “Why else would it feel appropriate to share relationship problems with complete strangers?“

Watch where you overshare
The woman’s secret was safe with Johnson, but psychologists say to be picky about who’s on the receiving end of your overshare. Blurting out too much information can be off-putting to some people.

Estabrook, the office worker, was so shocked at his colleague’s overshare that he hardly said a word in response. But should anyone else decide to confront him with a “live-in lover” overshare, he knows what he’d say.

“If someone told me that now, I would probably respond and say, ‘You know, I’m really happy for you,’” says Estabrook, who’s 41 and lives in San Francisco. “‘But I definitely would be careful about what you share with people you don’t know that well.’”

Or, as Twenge puts it, “Not every person you meet needs to know your every problem.”

Wade Stapleton wishes more people would remember that. At the end of a work day, the 42-year-old found himself in an elevator with a woman he’d seen around the office but had never spoken to. Like most elevator exchanges, their conversation focused on the weather — until she took it one step too far.

“Oh, the warm weather doesn’t bother me anymore,” she volunteered cheerfully. “I’m at that age where I have hot flashes.”

And just like that, she’ll forevermore be Hot Flash Lady, at least to Stapleton. “After that conversation, I don’t want to get to know her,” says Stapleton, who lives in Nashville, Tenn. “I know enough about her already.”

Now he’s careful to avoid her at every turn. “When I see her now, I try to go the other way,” Stapleton says.

Hot Flash Lady might do well to take the advice of Enoch, the self-described sweaty guy,  who’s figured out a way to structure his oversharing habits. He’s divided his social sphere into three groups — college friends, work friends and church friends — and he knows what he can tell to each group.

“I have friends I can discuss my gastrointestinal activities with, and friends I can’t,” Enoch says.

He pauses.

“That was probably an overshare.”