Arrays and linked lists are the building blocks of most other data structures. Both store linear sequences, but their performance profiles are worlds apart.
Arrays: Random Access Power
Arrays provide O(1) access to any element via its index because they are stored contiguously. However, inserting or deleting elements from the middle requires O(N) shifting.
Linked Lists: Fast Insertions
Linked lists excel at insertions and deletions because you only need to update a few pointers. The downside is that finding an element requires O(N) traversal.
Memory Layout and Caching
Arrays are much more cache-friendly because their elements are physically next to each other. Linked lists involve jumping around in memory, which can be significantly slower in practice.