Can the "hippocampus" be hijacked? Yes, it can. The hippocampus that plays a crucial role in learning can be short-circuited by intense emotion that's either ecstatically high or painfully low. But I'm not going to discuss the outliers of memory formation today.

The mind's slate can hold on an average of up to "7" thoughts, ideas, chunks, symbols, etc. That's the magic number - "7". When we perceive something, it takes "2" seconds (sensory memory) to register. Again, our short term memory, akin to the mind's slate can hang onto the 7 things we talked about. We then can use logic to either retain those stuff of thought, or jettison them. Otherwise, when we repeat those items, they will transfer into the realm of long term memory that is more than "20" seconds up to 20 minutes, 20 hours, 20 days, 20 months, 20 years, even protract to a lifespan. When something feels icky, ignore it. When you squabble, don't go around telling people about it. Do not replay it like a movie in your mind, neither- otherwise you will prolong the agony. The good side of the coin is, when you like to memorize useful information, you can try to remember by repetition. To remember something sweet, repeat, repeat, and then repeat.