Empathy: show and act on it
Empathy is necessary for good writing. You have to understand your reader's context and how they react while reading your text. If it is a sensitive topic, you have to anticipate how they will feel. If it is a complex, technical topic, you have to anticipate their doubts.
Sometimes you can to avoid that reaction. You use less aggressive words or more precise technical terms. But sometimes it is unavoidable. Your readers will be frustrated if you are informing them that they lost access to a repository due to a new company's policy. They will be confused if you are informing them that a new project will be using technology unknown to them.
The message itself will cause this reaction, not the writing, so there is nothing you can do about it, right? Wrong.
Just because a reaction is inevitable, doesn't mean it can't be handled. An excellent way to show you care about your reader is to explicitly acknowledge their feelings.
Use phrases starting with "I imagine your confusion now..." or "I understand this might be frustrating...". It shows empathy for the reader and tranquilizes them while they read the entire message. Then you can address those reactions more specifically.
Of course, this tactic depends heavily on you being right when speculating on the reader's reaction. So only use it when you are sure about how they will feel.
After you show your empathy, act on it
Also, its effectiveness relies on an honest concern for your part. If there is any sign that you actually do not care about how the reader feel and you are just acknowledging it without doing anything to minimize it, it is a counter-productive technique.
After acknowledging a reaction, complete the paragraph with a message that will help the reader deal with that reaction. If they are frustrated with a decision, explain to them the legitimate, logical reasons that led to that decision. If they are feeling confused with technical terms, point them to documentation that will educate them on the topic.