Simply put, a data structure is just a way to organize data. Why use them then? Well, the way that you organize data can really change how easy it is to use that data. That’s why data structures are important.
Think of it this way: it’s a lot easier to find a book alphabetically than it is to dig through a pile of unsorted books. In the same way, data structures help organize data so that it’s easier to use and retrieve.1.2 Intro to Algorithms