Answer: It’s the verbs that precede (come before) the object!
Some verbs require a gerund and some will require an infinitive. In the examples, we can see that the formula is “enjoy” + [gerund] and “decide” + [infinitive].
With practice, you will be able to remember which one is which.
Here are a few examples of verbs that need to be followed by an infinitive:
agree: I agreed to go to a party with my friend.
decide: The president decided not to participate in the discussions.
deserve: Everyone deserves to be respected.
expect: I expect to know my exam grade by tomorrow.
hope: We were hoping to avoid traffic by leaving early.