Here's why:

* Carbon's Bonding Ability: Carbon has the unique ability to form four bonds with other atoms, including itself. This allows for the creation of incredibly diverse and complex structures.

* Vast Number of Compounds: The number of known organic compounds is vast, far exceeding the number of inorganic compounds.

* Importance in Life: Organic compounds are the building blocks of life, forming the basis of carbohydrates, proteins, lipids, and nucleic acids.

While there are exceptions (like carbonates and cyanides), the vast majority of carbon-containing compounds fall under the umbrella of "organic chemistry."