I'm writing about this as a way to hold myself accountable.
I am often confronted with unwanted student opinions about assignments, directions, rules, or what-have-you. Typically, my response has been along the lines of, "I don't care if [you don't like it], this is what we're doing."
While factually correct, it's a pretty cold response, and I've always known it's not particularly effective. It may redirect the student's behavior, but it doesn't do anything to redirect the student's attitude, and that's arguably more important.
I'm so pleased to have finally identified an alternative response that does just that: "That's not what's important right now," or some variation on that theme. This response does not invalidate the student's feelings, and even gives me space to acknowledge them: "I know you don't particularly feel like doing this right now, but that's not what's important..."
I've actually remembered to use it two or three times over the past couple of days. I'm expecting more deployment in the future, especially as break time draws near. And so far, the students are responding more positively, too. I'm allowing myself to feel a tiny bit proud of this one.