Adolescence is far from a necessary stage in human development. In fact, it is a relatively recent invention. In primitive societies, there is childhood, then usually some rite of passage, normally coinciding with the biological event of puberty, after which one is considered an adult. As society has become more complex, and thus the period of education and dependency upon parents has become extended, there is a period when humans have passed puberty, and thus are "adult" in the sense of able to reproduce, and yet have not reached a stage of ability to survive independently in complex post-industrial societies. This stage is probably necessary in present technologically advanced societies, but not in agrarian or hunter-gatherer economies.
Yes I believe this stage in someones life is something we all have experienced. I know for me, it was 7th and 8th grade. I was a tom-boy and wore alot of nike and addidas clothes to school every day. I wore a pony tail or braids almost every day because it was easier with soccer practice after school. I also played volleyball before school so I did not care what my hair looked like.
It is a time in our lives where we are growing up and figuring out who our true friends are and how we want to grow academically. There will always be stresses and pressures in school and middle school is full of all of that. Some kids do not always follow the right path when they are at this stage, but being involved in sports/girlscouts/dance/clubs ins very important.
We look back at our "awkward stages'' and learn from them. Yes, maybe we do not look great in our braces and soccer uniform every day but we are growing and learning from all of it.