Here's why:
* Verbs describe actions or states of being. "Goes" describes an action (the act of moving).
* Adjectives modify nouns or pronouns, describing their qualities or characteristics.
For example:
* The car goes fast. (Goes is a verb describing the car's action)
* The fast car is red. (Fast is an adjective describing the car's speed, red is an adjective describing the car's color)