I always drive my customer away.

Who am I?

I am white when I am dirty, and black when I am clean. What am I?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

Do you know who was buried in John's tomb?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

Speaking of rivers, a man calls his dog from the opposite side of the river. The dog crosses the river without getting wet, and without using a bridge or boat. How?

Can you Find and name the hidden bird in the picture below ?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?