Humans have a fundamental need for a few things beyond food and shelter - tribe, territory and status. Human behaviour evolved from our ancestors the great apes - or monkeys as most people call them. Our monkey brains are still there underneath all our modern civilized veneer and they still have the same needs for tribe territory and status.
The tribe is the most important thing for a human monkey, membership of the tribe means life - and rejection from the tribe means almost certain death. Some monkeys could scrape a living without a tribe, but it's a tough lonely life with nobody looking out for you and nobody on your side in a scrap. Every group of humans has an in crowd - and an out crowd. Being in the gang feels great but being left out feels rotten (or so I would imagine!) and that harks back to a time when being in the out group meant starvation on the margins.
Humans are very sociable animals, our natural inclination is to be co-operative and social. Living on the plains and in the forests 50,000 years ago we needed to live cooperatively in the family group. Anybody outside of the group was an enemy and a potential threat. Nowadays we live in groups of 4 and 5 rather than the family groups of about 40 to 100 people of prehistory. We still feel the need for that kind of group though and it's no accident that so many companies are about this size.
Territory was important because it was our livelihood - and we still behavethis way even in modern urban environments - even in the big brother house, inmates carve out a little bit of territory and try and claim it as 'theirs'. We have a need for somewhere we can call our own - where everybody knows your name - and where people look up to you. Grafiti tagging is a symptom of a group of people without territory, they spray their tags around to try and claim some territory - and also status among their peers. If we can find more constructive ways for kids to feel ownership of their environment then we can stop tagging.
Monkey society has a very definite hierarchy visible from grooming. The monkeys at the bottom of the ladder groom those above them - if you don't groom anybody you must be the king! Knowing where you are in the pecking order is important - and not being at the bottom is important too. Modern society offers us lots of ways of being at the bottom of the pile - I don't have muscles like Schwarzenegger, I'm not as rich as Bill Gates, I'm not as famous as Amy Winehouse... My boss nags me, my wife nags me - even the cat nags me! It's easy to dwell on the negative in our massive multi layered society, what we need are ways that we can get status without being Bill Gates.
How can we find our own status? Find something that we can do well - if you are a keen gardener join a gardening club and help people out, do something for a charity, do something for somebody who needs it. Share your skills and your priveleges with those less fortunate than you and you will feel better and be halping them too.
However clever we think we are in the internet age we are still controlled by and large by the evolutionary steps of 50,000 years ago. We need to stop pretending that we are modern civilized people and make the kind of world our monkey brains needs.