What is the big deal about Big-O notation in computer science?

Question

How would Big-O notation help in my day-to-day C# programming? Is it just an academic exercise?

Answer 1

Remember that big-O tells you how algorithms scale with large numbers of inputs, it doesn't tell you witch algorithm is faster for your task.

Building pyramids is O(n) while sorting pictures of them is, at best, O(n log n) it doesn't mean it's quicker to build them than make a slide shoow.