Each new thought is a new iteration of the self. After each new thought, the previous thought becomes memory, and so too the previous iteration of the self. Sustained thoughts are sustained iterations of the self. Memories are visions of previous iterations of the self, memories of thoughts are recreations of previous iterations of the self. This is why memory is important, and memories affect future thoughts, this is why a recreation of an iteration will never be a complete recreation--new memories, experience have their input on recall.

Some drugs extend the ability to concentrate, the duration of a thought. Not all thought lengths are uniform. Sustained thought can be attained, and thus longer single existences of a particular iteration of a self. There is a funny feeling between one thought ending, or at the beginning of a new thought of remembering the self. That is, remembering who you were. Some drugs can contract the duration of a thought. If a thought length were reduced to an imperceptible shortness it is assumed that the self could be eradicated, or perhaps the isolation of a meta-self, which is a constant. Some people fear for the death of a previous self. Some people worship nostalgia this way. Some people fear the established prominence of one single self.

I would assume more people fear the death of of self and attempt to protract the existence, or recall to thus reanimate iterations of the self. Long conversations can extend the length of an idea. It is easier to remember things when the task is split between multiple people. The work of living is made easier by splitting up the work. Friendship is built upon this principle. A friendship is, among other things, an expectation from one person out of another person. These are expectations for how an individual will respond to stimulus, based on previous experience. Therefore an individual preserves the idea of another individual, and that second, preserved individual is tasked with meeting the expectations of the first. This protracts, helps to recall, and remain consistent certain iterations of the self. This is why repetitive conversations with people can be comforting.