Waterfall Process vs. Incremental Process
Different process styles are like different dance styles.
Different processes will put different levels of emphasis and effort into each step. Each processes may repeat steps, or take them in a different order.
We can think of each different process as a different style of dance. They are alike and unalike. There are people who prefer one style to another, and there are specialists in one style and generalists across styles.
For any particular song, some styles of dance are intuitive and comfortable while others are awkward. The same is true of applying a software process to a given development scenario.
What works for a global team on a multi-year enterprise software project may not work well for a start-up creating a consumer website. The process that works best for an engineering firm developing embedded software for a pace maker may be a nightmare to apply to an open-source project for creating an RSS reader.
Software processes are usually categorized as waterfall or iterative – although I first heard these categories from proponents of iterative processes (the "new" way) when they were getting a lot of press in the late 90's. Bias aside, the analogy works.