How de we remember, forget or distort memories?

When we remember, we are retrieving information from our brain. Events are stored in our brain as encoded sensory information that includes sights, sounds, and feelings. 

To remember, the brain looks for the information and brings it back to the foreground.

Remembering depends on cues that activates a memory. 

These cues come in the guise of visions, noises, smells, emotions, or locations that were concomitant with a certain event. 

For example, smelling the fragrance of a Sakura-scented soap might remind us of our Asian holidays. 

The smell acts as a cue that activates related memories.
Being able to remember an event depends on attention, the frequency of recalling, and the time separating us from the occurrence. 

Information that is frequently remembered is easier to retrieve because the neural pathways connected to it become more robust. 

Information that has not been accessed for a long time will be harder to retrieve, because it may require stronger cues to activate it. Stress, fatigue, and a scattered mind can also make remembering more difficult.

When we remember, our the brain rebuilds events by merging the stored information with current data.

Memories are not retrieved the same way a recording is.

Remembered memories are not completely accurate, because they are merged with and are heavily influenced by our current mood, emotions, suggestions, auto-suggestions, current beliefs, and changing perceptions. 

Memories are accurately described as a reconstructive process, not as a perfect recording of past events because they can be updated or altered.

All this explains the reason why we remember some experiences and we forget or distort others.