Sociology is the study of human relationships and institutions. This is a pretty broad category, spanning from religion to family units to crime patterns. Basically, what sociology seeks to understand is "how human action and consciousness both shape and are shaped by surrounding cultural and social structures" (UNC at Chapel Hill).
This knowledge can be applied to almost any professional career to help you better understand your bosses, colleagues, and clients. By understanding the different ways the people work together, you can more easily accommodate the demands of the people with whom or for whom you work. This will lead to higher satisfaction rates with your job. It can also help you understand the motivations and reasoning behind other people's decisions, which in turn will allow you to not only make better choices yourself but also get along better with those people.