Answer:
The man who invented it doesn't want it. The man who bought it doesn't need it. The man who needs it doesn't know it. What is it?
Searing 'cross the pitchΒ-black skies, I scream in celebration, Yet moments later, my outburst through, I am naught but imagination.
Always old, sometimes new. Never sad, sometimes blue. Never empty, sometimes full. Never pushes, always pulls.
Take one out and scratch my head, I am now black but once was red.
I'm not man's best friend, I'm their enemy, I can mark your end, yet you do not see me, I am very small, but very tough, If you have me, then you have it rough.
What is so fragile that saying its name breaks it?