Why do (sometimes) seemingly unimportant moments really stick as detailed memories, and some seemingly very important moments are hard to recall?

Question

At times, apparently mundane memories are really easy to recall, and moments you think ‘I want to remember this in detail, even gonna do an eye-camera pan of the scene’ don’t come back that easy. Why?

In: Biology

Answer 1

All seemingly good answers especially about forming memories based on external stimuli. Smells are often very good catalyst for memory formation as well. Like how when you smell chocolate cake baking, and it triggers a memory of a birthday you really enjoyed where you also enjoyed chocolate cake. The brain (not unlike a drug addict) is always looking to feed the dopamine receptors. Even if it only a fleeting memory.