Information: Cultural, identity problems
Intolerance, ignorance and fear cause a lot of problems, most wars start because of differences in colour, race, or religion. People can be or feel excluded, if they belong to some groups, for example:-
Racial or religious groups
Deaf or blind
Past criminal history
Knowing who you are and finding out about your cultural background, sexual orientation, and beliefs (political, religious, racial) is part of life, not just in teenage years.
Its important to accept difference, and tolerate other peoples strong beliefs (like the examples above, or like which football team, band or group to follow).
Arguing and talking about difference is OK, putting people down or being violent or excluding people, is not seen as acceptable in most societies.