Deja Vu

It's that feeling of "I've totally done this before" when you're sure that you haven't. The strange experience of deja vu involves having a feeling of prior knowledge in a situation that is completely new to you, and it happens to many people throughout their lives. But why does it happen? Are we able to see the future in a way? Is it happening because we might exist on multiple planes of reality and our memories are getting mixed together because science? Not really, the answer is actually far more simple. Psychologists and scientists conducted a study to determine the origin of deja vu and found that while we have a very good memory of objects, we don't have a good memory of the configuration of said objects. If you are in a place that has some unfamiliar objects, but they are set up similarly to a situation you have experienced before, you'll experience deja vu. Like if you're on a trail you've never been on before, but it's similar to a trail you've hiked in the past, you'll feel like you have, in fact, been on the trail before. Essentially, deja vu is an overreaction of your memory to tell you that you are in a familiar situation. 

https://www.psychologytoday.com/blog/ulterior-motives/201001/what-is-d-j-vu