As a career-long Girl-in-a-Boys-Club, I (apparently) decided early on that I needed to be tougher, smarter, faster and generally work harder than those around me. That'll show 'em! (Who, exactly, was I trying to 'show'? No friggin' idea!)
Of course, what that led to was me saying, "Yes!" to everything that ever came up.
New project? Yes!
Hostile client? Yes!
Problem-child employees? Yes!
Last minute business trip? Yes!
Absorbing someone else's job? Yes!
Yes! Yes! Yes! Yes!
Of course, the problem with always saying yes, is that eventually your plate is really too full to hold anything more. By always saying yes, I'd feel like I was being taken advantage of, and I'd start to get resentful.
In my case, that always meant at least one of the three following things would happen:
I start dropping the ball and not doing my job well.
I so overly exhaust myself trying to keep up that I start getting pissy with everyone around me.
I would start fantasizing about quitting.
In hindsight the pattern is so clear it's actually almost funny. The most ridiculous part is that I didn't fully appreciate at the time how much I had created that situation myself -- and that it was within my own power to do something about it. If I'd curbed my YES! habit just a bit, I might not have ended up so resentful that "I quit!" felt like the only reasonable response.
Not saying Yes! isn't the same as saying No! I was recently reviewing some techniques with someone struggling with this exact same problem. Let me know if you have any others to add to the list:
Make a list of the things you REALLY care about doing well, so you are super clear what is most important when priorities inevitably collide. Talk the talk, and then walk the walk. Being distracted with white noise is very easy when you don't have your eye on a specific target.
When asked for your opinion on something that you really don't have domain expertise on, answer with a question, "What do you think we should do?"
Instead of thinking in black and white terms (Yes vs. No), start incorporating negotiable language into the discussion, "I'd be happy to help out with that, if you would be willing to take over XYZ to make room in my schedule."
Physical triggers can be very useful when trying to break a habit like saying Yes! Brene Brown spins a ring she wears three times, I know someone who snaps a rubber band they wear on their wrist, I tend to click my pen at least three times. Something small to help you catch yourself and think before you immediately Yes! your way into another commitment.
Instead of agreeing to take something on, recommend someone else who can (or should!) be able to do it instead of you.
Use your calendar. Block off time for your priorities, and feel free to reject meeting invites that you're being invited to out of habit. The meeting-after-meeting habit is the norm in some places, and it just leaves you to do your actual work at night. Reject a meeting, and then resist the urge to justify why!
Accountability partners are a huge help. If you don't have one, then keep a log -- how many times did you catch yourself before saying Yes!? And what techniques are working with different people? Refining how you do this gets easier when you start watching for how people respond and then adapting accordingly.
Start small, give yourself a break, and remember that you have probably trained people to bring things to you because you've historically always said Yes! So it's not just your own habit that has to change -- it's their's, too. But the good news is that by changing yours, you won't really give them much option. But you are going to need to be consistent.
Oh, and in case anyone thinks this problem is just limited to work: I've never, ever met anyone with a Yes! habit that was limited to the office. Both the habit and the resentment that follows tend to show up in personal relationships, too.