Why do people find it difficult to realize the true essence and purpose of existence?

If an oil lamp is lighted, the flame always goes upward. Similarly, water always flows downward. A small child has a fascination for sports, music and fun. This is a natural phenomenon, which, in other words, can be put as the will of Lord Sri Krishna.
Thus, the vision of all creatures, right from a small worm to a mammoth elephant, is outbound. Since we have taken innumerable number of births earlier, and in all those births, our vision was outbound, it is very difficult for us to turn our vision inward in this birth.
The true purpose of existence can be understood only if one attains a Guru, who, not only knows the true purpose of existence, but has also experienced it.