No one taught middle school kids how to deal with emotions. That's because the adults around them don't know how to deal with them. We are educated in a math

No one taught middle school kids how to deal with emotions. That's because the adults around them don't know how to deal with them. We are educated in a math & science heavy society. That's good. However, it puts the focus on evidence. Emotions don't leave much of a trace unless you act on it. So we use behavior resulting from emotion as evidence of reality and ignore the experience of reality. Then we say, "be real" and cut off an entire spectrum of reality -- that of experiencing emotions. These are the makings of the shadow side, the Jungian shadows. When you disown or suppress experiences, then they get stronger. So yes. We have not grown up because we don't know how. Or at least, no one told you how. You cannot "get over" negativity. That's a form of rejecting something you don't want to feel. The only way out is to accept the experience of it as is, without rationalizing it and without acting on it. That's probably the hardest thing you will ever do in your life, but the most important if you want to grow as a person. There are several methods by which one can do this. One of them, called vipassana, was taught to some prisoners with great results (http://www.dhammabrothers.com/ http://www.dhammabrothers.com/). However, you don't need to be a criminal to use this.