To forget is to fail to remember
There are two main theories of how people forget
The theory of decaying implies that memories fade over time. You can picture this like the ocean and sand. Someone draws something in the sand, and the rolling waves eventually make the etching fade away.
eventually the message fades away like an old, forgotten message
Next, this theory includes the idea that memories can be blocked by other things in the brain. Therefore, you can not access that moment in time. This time, the wave does not erase the message written in the sand, but another kid comes and writes over it. This makes the writing harder to read.
Writing over this would make both messages hard to decipher
The hippocampus is the part of the brain that deals with making memories, and ultimately forgetting them. The picture below shows you where the hippocampus is located inside the brain.
The blue part is the hippocampus, a part of the brain
Memories become "fuzzy" overtime, slowly fading into oblivion. Sometimes, we can remember certain instances clearly. Like if we've seen a certain item or something of the sort. However, maybe we can not remember exactly where we've seen it before. Have you ever walked into a room and not even remember why you went in it? There is no clear answer to why this happens, but it might be something to do with short term memory. Forgetting can be frustrating, but sometimes, it can be good. For example, forgetting the moment you tried a nasty food would be amazing. On the other hand, forgetting someone's birthday would be the exact opposite.
Over time, most memories will fade, and be replaced with new ones. Whether it's with interference, decay, or something else, forgetting will happen whether you want it to or not.
Cherry, K. (n.d.). 4 Explanations for Why We Forget Things.
Cherry, K. (n.d.). Forgetting: Some of the Top Reasons Why We Forget Things.
Shaw, J. (2016, September 12). Why Do We Forget? Retrieved March 10, 2017
Vogel, E. K., & Drew, T. (2008, November 03). Why Do We Forget Things?
Why do we forget information? Find out in this fascinating article exploring the purpose of forgetting. (n.d.). The Art Of Forgetting: Why The Mind Forgets Some Memories.