A tribal mentality has been a part of human existence for thousands of years and is still a strong part of it.  In the news we often hear stories of tribal leaders in places like Afghanistan and Pakistan having more power over the local people than the national government.  In the western world, we don't have tribes in the same sense, but we have substituted for them with similar types of organizations that are not usually geographic.  Groups such as churches, gangs and even businesses.  These organizations, much like tribes, usually have a set of rules that the members are expected to live by.  The rules may be written or just understood.  And when you are in such organizations, it is difficult to ignore those rules and behave differently.  A gang may have certain rules about who you can hang out with or date and violating those rules can result in violence against you.  With other groups, the punishment for violating rules may not involve violence, but may be more like being ostracized by other members of say your church for something like dating a person who belongs to another church or being passed over for promotion by your employer because you broke some rule such as participating in a political demonstration.  These things can make it difficult to be different in any way.
    With spiritual development, this tribal mentality can often interfere with your willingness to engage in spiritual activities that are not approved of by some group you are part of.  You have to make a choice sometimes to ignore the group rules in order to save your own immortal soul and the souls of your loved ones.  Sometimes, that may mean leaving a group you belong to such as a church or social club, but often that is not necessary.  Even though a particular church doesn't teach it's members to develop spiritually, they don't usually forbid it.  Also, you can join a spiritual organization that does encourage spiritual growth.