One experiences select elements of an event due to attention. The criteria of selection depends. This phenomenon exists to conserve energy.
Attention: the allocation of the body's resources to a specific purpose.
Two types: voluntary and involuntary. The latter is the default. The former requires resource allocation, which uses energy.
To control attention:
By controlling what to focus on, one sees more of what one seeks and less of otherwise. This act of toggling attention is a skill that requires practice.