Answer:
What goes up but never comes down?
A young man wants to have it, but when he has it he no longer wants it. Blade in hand he attacks it And does his best to remove it. Yet he knows that it is all in vain.
A job that involves sitting in a highchair, wearing a black gown and smacking things with a mallet
Hearing something unexpected or touching a live wire can have this effect.
A mechanism to discover who is following you.
I am a room that has a roof but no walls. What am I?