Here’s a really effective way to diminish your credibility in the workplace and reduce your own confidence: say “I’m sorry” a lot.
People – and by “people” I mean “women” – say "sorry" all the time. Most professional women say it far more than they are aware. It creeps into all kinds of conversations:
“Sorry for interrupting . . .”
“Sorry I didn’t get this to you sooner.”
“I’m sorry you didn't have time to finish this.”
“I’m so sorry that [train delay, argument, spill] happened to you!”
In addition to actually speaking the word “sorry,” it’s possible to communicate “sorry” with many nonverbal behaviors, the embarrassed shoulder shrug (usually accompanied by closed-mouth exaggerated smile) being the most prominent.
“I’m sorry” can mean lots of things. It can mean “I did something bad” like cutting you off, cheating on my taxes, or not leaving a final muffin on the communal plate. Mostly sorry-as-apology seems to apply to non-tragic situations where it's not clear that anything has even happened. It has the meaning, “Maybe I should have been more considerate, but I wasn’t, so I want you to know that I’m aware of my shortcomings.”
“Sorry!” can also mean, “I think you just criticized me, and I feel awkward and embarrassed being criticized, and I'm not sure what to say, but I need to say something, so I'll say I'm sorry.” Example: “Joan, there were a few typos on the prospectus.” “Sorry!”
"I'm sorry that you ..." can be an expression of disapproval. "I'm sorry that you didn't have time to review the documents" is an example. Most listeners would find this to be a pretty clear criticism (albeit a passive-aggressive one); yet my impression is that many speakers of such words are quite sure that they mean nothing of the sort.
“Sorry” can also be fishing for appreciation or expressing a complaint. “Here's the draft of the offering memorandum; I worked on it until 6 am but then had to go to an 8 am doctor's appointment, sorry I wasn't able to reschedule it.”
“I’m sorry” has a totally different use, as an expression of sympathy. It shows that you understand that an unfortunate thing that happened to a fellow human being, whether that’s an annoying conversation or something actually serious, and you want to show your sympathy. It’s a bridge expression, combining a feeling of “that sucks” with “I am concerned.” The problem is that it is vastly overused, and in my own experience, tends to add a distracting emotional element to things I think are pretty trivial. If I say, "I got totally wet in the one-block walk from the subway stop to my office" and a colleague responds, "I'm sorry!" I think, "huh?"
Men, by the way, use “sorry” approximately one-zillionth the frequency women do, at least in the professional world. Barbara Annis, who wrote an interesting book on gender differences in the workforce called Leadership and the Sexes, says that women use “sorry” as a way of bonding and creating harmony. She says further that women don’t always mean they are actually sorry when they say it – it’s just an accepted nice thing to say.
One of my professional goals is the empowerment of all women (especially those in the developing world, but that’s another story). So I will just lay out my opinion: women, you’ve got to STOP saying “sorry.” Just get rid of it. It’s holding you back, especially because most of the time you use it you are probably not even aware of it. For the time-being, our work norms are male-dominated, so if you say "sorry” a lot in professional settings your words are going to make you seem ineffectual, uncertain, and frequently wrong.
Do a “sorry” audit and figure out how often you are using it, and in what situations. If what you really mean is, “I apologize for something significant” then it might be okay. But if it doesn’t rise to that level, don’t say it. Second, save your “I’m sorry about your _____” expression of sympathy for things that actually matter. Saying “I’m sorry” when a colleague complains, “the traffic sucked,” doesn’t count. And if you hear female colleagues, especially younger ones, boarding the sorry express, clue them in. There are better uses for their energy than being sorry.