I had a co-worker some time ago, relatively young and new to the workforce, who, over the time we worked in the same company, got the No habit bad.
There are lots of reasons to say No, in pretty much every possible situation in life. Would you like a sip of cyanide? “No, thank you.” Wanna hook up? “Eew, no, sorry.” Would you be willing to do this illegal thing as part of your job? “No, I would not.” Do you want lima beans? “God, no.” Can you take my shift while I go to my aunt’s funeral? “No, I’ve got my daughter’s graduation that day.” And so on. As the #metoo movement has been forcibly making clear, the right to refuse must be taken seriously. But like many rights, you maintain No’s power and authority by using it when it’s needful.
In improv, almost the first thing you learn is that No shuts a scene down. If your partner says “Would you like some roasted giraffe kidney,” perhaps you could come back asking if it was locally sourced. That gives you and your partner somewhere to go. In the same way, working in a public-facing businesses you learn, not that the customer is always right (because really not) so much as that you want to find a way to say Yes. “Do you have this in size 10?” “No” stops the interaction dead in its tracks, but “I don’t think so, but we do have this in a 10, would you like to try it?” gives both client and salesperson somewhere to go.
To return to my long-ago co-worker: we were working in a business in which layoffs were pretty clearly in the offing (the guy playing the Darth Vader death march on the PA system is a dead giveaway). Because I liked my job and, more than that, really did not want to have to go job hunting, I put a good deal of effort into saying Yes. If something needed doing–even if it was not in my job description–I’d help out. My co-worker started out doing that, but the longer they were in the job the more likely they were to pull the “Not My Job” card, building a little fortress of I’m-Sorry-No around their desk. Were they busy? Sure, but so was everyone else. After a while, the No generalized to a kind of “standing on principle” reflex that left co-workers extending themselves even further because LACW (long-ago co-worker) dug in their heels and said No.
You see where this is going, yes? Bartleby the Scrivener famously says “I would prefer not to,” which in his case starts with doing the work he was assigned, and eventually leads to him “preferring not to” eat, and dying of starvation. When the layoffs came, LACW was in the first wave.*
Tiny children learning to talk go through a NO! phase when they get giddy with the power of refusing, of controlling what happens to them. It’s often referred to as the oppositional phase, but really, I think it’s just a period of finding your own boundaries and testing to see if they will be observed. Drawing your boundaries and making sure they are observed is very important. But one of the things you learn, working with other people, is that everyone has boundaries they want to have observed, but sometimes a job that has to get done may lie outside those boundaries. At which point consider Yes as a strategy.