A man spends a dollar for a lottery ticket and wins! He goes to town to claim his prize and his ticket number is verified. The man says, "I want my $20 million."
The clerk replies, "Well, we give you a million today and then you'll get the rest spread out for the next 19 years."
The man says, "Oh, no. I want all my money right now! I won it and I want it."
Again, the clerk explains that he would only get one million that day and the rest during the next 19 years.

The man, furious with the clerk, screams, "Look, if you're not going to give me my $20 million right now, then I want my dollar back!"