Whenever any group, especially a religion, holds itself out as being a "Noah's Ark" - that is to say that it holds itself out to be the only means of salvation, it should be considered to be a warning sign that the members may be subjected to cult-like psychological pressures and motivators.
Now, this is not to say that one should not feel either pride in their religion or that they shouldn't feel that it is the right one for them. They may even believe that their faith is the best one.
What is being discussed here is not this sense of loyalty that all persons should have towards their faith, but rather this information is calling attention to the underlying psychological reasons why we might be attracted to one of these "Noah's Ark groups."
A "Noah's Ark group" is one which goes beyond what would be considered a reasonable amount of confidence in itself, its doctrines, teachings, faith, even leadership. Instead a "Noah's Ark group" insists that there is no salvation outside of the "ark" (that is the group or religous organization itself) and that all those who fail to come into the group will without any doubt perish or otherwise be subject to damnation.
Most, but not all, "cults" could be classified as a "Noah's Ark group." For this reason, I use the cult term below liberally but keep in mind that some non-cult groups which have traces of cultic characteristics, such as Jehovah's Witnesses, may seem familiar under this rubric.
The following mnemonic may be useful in helping you to appreciate the psychological factors involved in the appeal of cults and other such "Noah's Ark groups." In the following, "THIS" refers to the group or religion in question.