Who we associate with can have a significant effect on our spiritual development.  If we spend most of our time around people who are very materialistic and don't believe in anything spiritual, their low vibration rate will have the effect of lowering our rate.   In the worse cases, they can be spiritual vampires that suck up our spiritual energy, usually without being aware that they are doing it.  On the other hand, being around other people who are developing spiritually, especially those who are already highly developed spiritually, will tend to help us raise our own vibration rates.  That is why, throughout the ages, mystic and Gnostic schools such as the Essenes have been very selective of who they allow to join them and, even then, new members are always on a trial basis.  It is also why, for example, ministers of the International Community of Christ do not do prison ministry.  We don't object to those who do try to bring religion to these people, but for those who have worked hard to increase their spiritual vibration rate, getting around such people regularly would harm them considerably.  This is the same reason very advanced spiritual people after retreat from the general society as in the often comically depicted guru on a mountaintop.