The pasteurizing process damages the honey and removes many of the natural flavors, nutrients and antioxidants that are found naturally in honey. Then processed honey is fine-filtered to remove any small particles of pollen, beeswax, bee glue and other nutrients.
The main reason manufacturers use this damaging process is to make the honey look nice and clear on the shelves and to keep it in its runny, easily squeezable state.
The downside to raw honey is that it will crystallize quite quickly. This is a small price to pay for a far superior product.