Why is absolutely pure simple harmonic motion not possible?

(N/A) Absolutely pure simple harmonic motion $(SHM)$ is not possible in reality because it requires the absence of all dissipative forces,such as friction,air resistance,and viscosity.
In any physical system,these dissipative forces are always present,which cause the energy of the oscillating system to dissipate over time.
This leads to damping,where the amplitude of the oscillation gradually decreases,eventually bringing the system to rest.
Therefore,$SHM$ is an idealization,while real-world systems exhibit damped harmonic motion.