so many people have bought into the convenient idea of showing them, regardless of whether they are valid, or regardless of whether their emotional outbursts affect others.
A lot of people do really think that it's better to show emotions than control them. I'm not saying that it isn't okay to show them... It's just that one should know how to control showing it so that it will not end like a violent emotional outburst. Me and my sister often have fights on that topic because she thinks that controlling emotions is repressing them; in fact, I didn't suggest repressing them, rather it's just she needs to learn controlling them. She's emotionally volatile these days, and I really tried to understand her because I've been through that phase. I'm constantly reminding her to control her emotions and not let them control her because her negative emotions are really strong and contagious. Personally, as much as possible, I try to control how I absorb and react to these emotions because I know they will really matter and make a difference.
The problem is that people claim that their emotions are "theirs", but can't choose not to react when they feel them. Without emotional control, the emotion isn't owned. And emotions are responses to perception, so they will feel something, even if it isn't a valid thing to feel - so people respond to a misunderstanding, as if the reaction is appropriate, even when it is not.
There is definitely a difference between repression and control. Yet, the people who aren't willing to learn control, aren't willing to admit the difference.
Exactly, a person can't fully own his or her emotions if he or she can't control them; rather, if he or she lets his or her emotions control him or her, then it is like letting one's emotions own himself or herself.
As for explaining to her the difference between repression and control, it's truly hard since she's probably one of the people who failed or chose to fail to see the difference between those two.