Generate an analogy for the phrase "castle in the air"
Dreaming of a "castle in the air" is like painting a masterpiece in your mind, but never putting brush to canvas - it's a beautiful idea, but it has no foundation in reality.
Complete the following task based on the instruction and optional input provided.### Instruction:
Generate an analogy for the phrase "castle in the air"

### Output:
Dreaming of a "castle in the air" is like painting a masterpiece in your mind, but never putting brush to canvas - it's a beautiful idea, but it has no foundation in reality.