Rebuild the missing context
Assume the recipient will not remember every date, promise, or earlier conversation. For a message about how to resolve a difficult work handoff, use this factual base: use recent examples, observable impact, and the work requirement rather than labels about personality.
Say what needs to happen next
State the decision, information, or practical action you need and include a real deadline only when one exists. Ask for a specific change, decision, or working agreement and choose a time to review it. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Avoid making urgency into pressure
Do not diagnose, gossip, embarrass a colleague, or turn one incident into a judgment about their character. Move harassment, discrimination, threats, health risk, and retaliation into the appropriate protected process. Do not make the other person responsible for reducing the discomfort that prompted you to write.