My last post discussed the dangers of continuing to talk—particularly after others have accepted our recommendations. Having convinced the people around us, I argued, it’s time to curtail the monologue.

And now let’s consider another situation in which most of us are ill-equipped but well-advised to zip our traps: when a workplace colleague, to our unmitigated amazement, promises to do something better or faster than needed. It can definitely make life more negotiable.

Imagine you’re expecting your colleague to send an important report by the end of the following week, for example, but she unexpectedly tells you that, “I’m working really hard to get it done by tomorrow.” Caught so substantially off-guard, how would many of us respond? Probably by admitting that, “Oh, I actually don’t need it until next week.” Or imagine another colleague who tells you he’s staying late to prepare an unbelievably persuasive presentation on your behalf. Wouldn’t many of us politely thank him but tell him it doesn’t have to be perfect?

Upon reflection, I think most of us would admit having made such a statement. But why? Why would we tell somebody who wants to do something quickly and excellently to instead do it slowly or poorly? Seen in that light, such statements appear to have little logical basis.

And there’s a strong logical basis for avoiding them! By not telling other people to take it easy, for example:

1. You’ll probably (and obviously) get a better or faster product.
2. You’ll probably, but less obviously, set a useful precedent for the quality or timeliness of future work products.
3. You’ll probably, and least obviously, help the other party feel better about their own hard work. Why? Because people like to think they are acting rationally and efficaciously. If they’ve been working their tail off on your behalf and you tell them at the last minute that you didn’t actually need them to do so, how will they react? Probably by thinking: “Why in the world have I been working my tail off?” Or “why didn’t they tell me that two weeks ago?” A last-minute revelation that we would’ve actually accepted a slower or poorer product is not likely to leave them smiling.

Now, like any piece of advice, this one has definite limits. Indeed, there’s at least one situation in which you’d want to completely ignore the preceding advice: If you see someone working themselves to the bone, missing out on family time, or letting their blood pressure rise to dangerous levels, you’d probably want to intervene in the interest of honesty, health, and wellbeing. But in the majority of cases, when someone is simply trying to do something quickly or excellently and not harming themselves or anyone else, it’s probably in everyone’s best interests to simply let them exceed your expectations. And what if you feel a bit guilty about letting them do so? Well, you can always reflect your appreciation in their performance review or a glowing letter to their boss.