1. Albert) Why on earth not?

2. And why on earth would he run?

3. Why on earth didn't you tell me the truth?

4. Why on earth would you want me to play the piano?

5. One said, "Why on earth would you care about the personal computer?

6. Why on earth would I trust the word of a lying little savage like you?

7. We haven't seen each other in forever, why on earth would you bring a little leech with you?

8. Why on earth are they called Conic sections? So to put things simply because they're the intersection of a plane and a cone

9. Especially given how expensive lawyers are these days, why on earth would the culture of 'must mark up documents to show value' persist?