We recently had a situation where I sprung a spontaneous outing on my family. 15 minutes to get ready. Some were more than fine with this, while this sent one into panic mode.
They approached the parents angrily stating, I'm not going and we can't make them and 15 minutes notice isn't enough and I'm in the middle of things.
I was more than ok with that, certainly, no worries, you're welcome to stay home, no obligation to come.
My partner was instantly responding in the same manner and the two argued for a bit before I broke it up and calmed them down.
Some time later my child raised it, still angry about it having happened. I mentioned there was no need for them to get angry because I would never have made/expected them to come, it was just a suggestion for those who could or wanted to.
This lead us talking about them trying to be assertive, and this got us onto assertion vs aggression.
Assertion is making a request in a firm yet non confrontational way. Aggression is making a request with anger.
They said, they thought they were taking control and I explained that once you're angry you've lost control. When being assertive you remain in control and I gave him demos of what being assertive looks and sounds like.
It is so important to teach your children these lessons while they're at home with you so that when they venture out into the adult world they have the skills to navigate through difficult and troubling situations.
