Example: A new restaurant opens up in town and people are saying that the food there tastes great. Feeling hungry, a man named Tom decides to drop by. After he is done eating, he's not impressed, even feeling a little disappointed. Thus, he might say that the restaurant's food was 'not all it's cracked up to be.'
Note: The origins for most phrases and sayings cannot be said with a certainty. What's provided are theories that may be plausible to how a phrase originated, but not necessarily so.
In addition, quotes that contain a particular phrase may be taken from old newspapers, poems, or books that were written centuries ago, but this by no means confirms that the phrase originates from said newspapers, poems, or books. In all likelihood, if an expression is being used in a newspaper, it's probably already a well known saying and is from an older time.
* A friend of mine named Ashley recommended me a movie, saying it was one of her favorites. I was excited to see it, but after watching the movie, I would have to say that it's not all it's cracked up to be.