Actions to take: Get out of the mindset that positive feedback is a commentary on something an employee did well and negative feedback is commentary on something they did poorly. Instead, push yourself to think of all feedback as "advice to encourage effective future behavior." Review your feedback to see if your phrasing is emotionally charged in either direction.
Last semester, I gave one of my students the following feedback: "When you take your time and make sure you understand exactly what the question is asking, you provide detailed, insightful answers that address novel aspects of the issue others don't consider." Is that positive feedback or negative feedback?
The student frequently gave impressive answers with details that hadn't occurred to others. They also gave answers that missed the point of the question from time to time. I was giving this feedback at the end of their exam, which had examples of both. The feedback was neither positive nor negative. It was simply advice about how to be effective.
This ambiguity is what you want out of your feedback. Ideally, the middle step of the formula ("when you do X, it has Y impact") could be given after your employee did that thing right or after they did it wrong, with little to no tweak to the language. The only difference in phrasing positive or negative feedback is the last step on the formula. With positive, you finish by saying "Keep it up" or something similar, and you say "Can you work on it?" with negative feedback.
Why does this matter? Shouldn't negative feedback be a little negative to help make the point? Shouldn't positive feedback be a little positive to celebrate the win?
In short, no. You are not thinking of feedback. You are thinking of rewards and punishments, praise and reprimand.
When you are crafting feedback for your employees, always keep the purpose at the front of your mind. Feedback isn't a celebration of good work (Please do that too—just do it elsewhere with other words). Feedback isn't a reprimand for bad work. Feedback is advice for how to do the work effectively in the future.
Advice isn't emotionally charged. Effective work is effective work regardless of what happened in the past. If you make your positive feedback sound positive and your negative feedback sound negative, your employees will engage with the emotional element that you are adding to your feedback. They will anticipate either feeling good or feeling bad. That will happen somewhat no matter how you give your feedback, but you don't want to add to it. We should work to make feedback sound as routine and as emotionally mundane as any other everyday work communication. If feedback is an emotional rollercoaster for your employees, it will be much harder on them and on you.
Review several pieces of feedback that you've given in the past week or so. Ask yourself, "could this same feedback, phrased the same way (or with very minor tweaking), be given if the employee had done the opposite?" Reflect on your tone. When you are giving feedback after your employee did something right, is your tone celebratory? When you are giving feedback after an issue, is your tone darker or more serious?
If you find that you are committing these errors, here is a handy trick to help. When you are composing your feedback, imagine your employee doing it the right way in the future. Do this regardless of whether the prompting behavior was positive or negative. Spend two weeks doing it before every piece of feedback you give. You will train your brain to think about all feedback the same way, so your delivery will come out the same way.
By thinking about feedback as advice with no positive or negative emotional element, you are making feedback easier. You will have an easier time giving it, and your employees will have an easier time hearing it. We do easy things more frequently than hard things. You want to be giving feedback as frequently as possible, so take every step you can to make it easy.