Here's why:
* Intransitive verbs do not take a direct object. They describe actions or states of being that are complete within themselves.
* "Break" - You can break something (transitive), but you can also break (intransitive, as in "The vase broke.")
* "Think" - You can think about something (transitive), but you can also just think (intransitive, as in "I think, therefore I am.")
Let me know if you'd like to explore other verb types!