We need to differentiate ourselves as a basic premise for developing self-esteem. It's best if we continue accruing it (along with heaping portions of humility, natch) throughout our lives, ideally without tipping over into raging, unbridled narcissism.
Yet we also need to belong, to enjoy the company of others, cherish and establish families, build communities, nation-states, and so on. That involves selflessness, compassion, empathy, effort, and altruism, to name a few qualities -- many of which are in rather short supply in a modern, hyper-connected era drunk on the cashflow made possible by exploiting peoples' baser instincts and weaker moments for a healthy profit.
It can be a central challenge to continually find and re-forge that delicate balance between solitude and togetherness during the many major and minor inflection points of our lives.
See also: In-group/out-grouping, scapegoating, confabulation, Dunbar number
perhaps the hyper-fragmentation of interests & ideologies may present a problem for nation-states, & religions— barb dybwad (@doctorparadox) September 24, 2015