Example:

John Doe, while reading late at night by the window notices the sun going down. He realizes he is out of lamp oil. He says to himself, “I wish there was a way to make light without lamp oil when the sun goes down so I could finish my book tonight.” He sighs and goes to bed, and plans to get up early in the morning to finish his book.

Thomas Edison, reading the same book, wishes for a bit more sunlight to come through the window too, because he would really love to continue reading the book as well. He has also run out of lamp oil. So, he thinks of a way to invent the lightbulb. The next day, he wakes, and is determined to never have to stop reading because of the sun going down for the day again. He invents the light bulb. Now, everyone uses light bulbs. He thought of it, dreamed of it, AND MADE IT HAPPEN.

The difference between the two men above is that Thomas Edison actually started making the lightbulb. He didnt just dream…. he got started, and did it.