A Bed of Thorns or Roses

Why do beautiful flowers like roses have such vicious thorns? Are they more prone to being attacked by bugs and other nasties, just because of their beauty, and need a defensive mechanism?
Not quite, as many other thorny plants in arid regions aren't always very pretty, but the thorns they have are vital in preserving those plants. It helps with water loss by reducing water condensation, and in the case of cacti, they help collect water from the air. Thorns also protect the plants against herbivores. So, thorns are vital to the survival of some plants.

Life swings between a bed of roses and one of thorns.
Why do we also have to deal with thorns along the path of life, and how do we survive? Do we really need to experience those nasty thorns to appreciate life again?l