How did humans lose their tails?

Picture a place where people all around you had tails. Well, climbing trees and swinging around would surely be a lot easier. Besides, nearly all the vertebrate groups have it. Reptiles use it for self-defense and attacking prey. It helps cats and dogs to balance and communicate. Birds use it for navigation. 

Our ancestors had it too. But why were we pushed out of this 'tail tradition' going on?

THE PROCESS BEHIND THE LOSS OF TAILS

Apoptosis is a process, a type of programmed cell death that's sort of wired into the development of multicellular life. It is a sort of self-destruction of biological cells which is the process behind the loss of tails. 

NO USE FOR TAILS

With evolution, humans dropped out of trees and embraced bipedalism, choosing to walk on twos. Tails would have affected the balance required to walk. Tails were great for balance in the trees, but natural selection proved that they were just unnecessary. Natural selection is a process of evolution; it's the way species change over a period of time. It picks on the best adaptations to fit in the environment and runs on the principle of Survival of the Fittest, where the best and most adapted survive and the rest die. 

REMNANTS OF THE TAIL

Now the only remnant of the tail is the coccyx or the tailbone, which consists of three to five vertebrae. Why do we still have the tailbone? Well, it serves as an attachment point for several muscles, tendons and ligaments.