In the sentence: "The most important things in my life are making money, traveling abroad, and to live well," what is the grammatical error?

In the sentence, "The most important things in my life are making money, traveling abroad, and to live well," the phrase "to live well" creates a parallel structure error. The other elements in the list, "making money" and "traveling abroad," are gerunds, which are the -ing forms of verbs that function as nouns. For the list to be grammatically parallel, all items should maintain the same form.

Using "to live well," which is an infinitive phrase, disrupts this parallelism since it does not match the gerund forms. Therefore, replacing "to live well" with "living well" would correct the error and maintain the consistency in structure among all components of the list. This emphasizes the importance of parallelism in lists for grammatical correctness and clarity in writing.