Question

Why do we forget things? (Like brain drain)

Answer 1

Over the course of our life, many exciting things happen. You remember the most exciting events, you forget the ordinary day events. Plus, your brain has something like memory storage. If you go past your limit, your brain automatically deletes some stuff.

Answer 2

There's not enough room to remember EVERYTHING. Besides, some things are more important things to remember, so the brain "deletes" them.
Hope this helps~!
~{Oh Mrs.Believer}