"people", when used as the plural of "person", requires a verb form that's also in the plural. In your example, "most people" refers to multiple individuals, so you need the plural.
Unrelated to your example, but useful to know: the word "people" could also be used as a singular noun, but with a different meaning - it refers to a group of human beings with a common culture, tradition, language, etc:
Americans, as a people, value hard work and not giving up easily.
It also has its own plural:
The peoples of South America, one of which was the Incas, had rich cultures and complex belief systems.
Most of the time, however, you'll see "people" as the plural of "person" or "human being".