Can you find the missing piece of the Porsche?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

The more of this there is, the less you see. What is it?

The dirtier I get, the whiter I look. Who am I?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

Fate has decided that you will only be pleased to meet me when you need me

Maybe that is why, when I am working, I start working

However annoying I may be to the regulars, the little ones are always inspired

I will always be waiting if you try to reach me

How many of you can guess my name, let me see

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

How many times can you subtract the number two from the number fifty?

What is the riddle which can be asked all day with a different correct answer each time.