A renowned psychologist, Brentano, studied human psychology, especially human consciousness. He pointed out that the basic nature of consciousness is that we often don’t notice what we already have, but we strongly feel the absence of what we lack.

“This means that feeling the lack of something is a natural part of being human.

As a famous couplet says:
Duniya jise kehti hai jaadoo ka khilona, mil jaaye to mitti hai, kho jaaye to sona.