Repressing impulses for the sake of order and peace. Looking back now on my teens, this was a major part of my life. I'm much more outspoken now concerning anything I find important, though can still repress the shit out of myself when it comes to stuff I don't value. But even when I don't fully repress something that could potentially damage the peace, I still tend to keep a damper on things, expressing myself slowly/softly, if I feel it could inflame a situation negatively.
A positive side to this, when used as a strength, is that I try to speak in the language of the people I speak towards and place myself in their situation rather than purely focusing on just my side of the story. And this can lead to a lot of positive things.
But particularly when I was immature and unaware of my repressing nature, it was rarily a good trait. The last ten years, and most notably the last two or so years that I am interested in typology, I've really been able to work this into something positive.