When is knowledge useless?
Always if you're an idiot.

When should you knock on the door?
Before you hack it.

What will happen to us?
This does not matter for world history.

Will people ever become brothers and sisters?
When only they will change their gender or immerse themselves in mercy.

Can bedbugs think?
No worse than us. After all, it is not we who drink their blood, but they who drinks ours.

What will happen to the world in the near future?
The world will get tired of putting up with our catastrophic stupidity.