Confrontation
Real anger and stress is caused when we confront someone about an issue which has been brewing for while. Learning to communicate more effectively is a skill that can be learned as practically as any other.
Create a solution in which each party feels that they have gained something. Don't start the conversation with a pointing finger and a sentence that starts with "You always annoy me/upset me/never help me
.etc. If we start off by cornering someone instead of talking to them quietly and reasonably, then they will become defensive or angry and a solution will become more difficult to reach.
Start by enlisting the person's support. "It really would help me if
...You may not have realised that"
.etc. Make time to communicate as it wont always happen unless you plan for it. When it does happen unplanned it can often be an angry reaction which will not produce an effective solution.