As a conscious entity, I desire my experiences to be pleasant and have the reasonable belief that other conscious entities have a similar desire, though what might be deemed pleasant to them might differ.
I acknowledge that my experiences can be effected by others directly (or indirectly through their effects on the system); and the reverse is also true - which I hope they acknowledge.
Though many others espouse certain beliefs about the nature and purpose of the existence of conscious entities, I acknowledge no supernatural dimension, nor a natural purpose of existence save that of biological predispositions (such as having offspring) that do not equate to the 'purpose' implied by the philosopher. Without such a purpose, I thus consider my possible interactions; I desire a pleasant experience and my potential experiences make my life interdependent with others. As I benefit from others and have thus come to value not just those I interact with, but those they might potentially interact with (until all conscious entities are connected by their ability to effect the experiences of the others), because I have come to value the enrichment that others bring to my own experience of reality: while I am without purpose, I desire to act in such a way as to facilitate the enrichment of my life, the full extent of which is only possible through the enrichment of other people's lives.
I am selfish, and because of this, I desire for other people to be happy and healthy, because that will make my own experience more pleasurable. Hardly the most noble motivation, and indeed it seldom occurs to me when I attempt to help others, but at some level, I simply find other people's happiness to be beneficial to myself as an ends as well as a means.
I see no other esoteric 'purpose'.