Emotions can quickly hijack other brain processes, diverting attention, and determining what will be remembered, and what won't. In the figure below, higher levels of anxiety made it harder for the amygdala to recognize happy facial expressions.
So what to do? Obviously emotions can be manipulated in a positive way in order for experiences to be made memorable (teaching, advertising, etc.) - but different problems result when negative feelings or anxiety create a virtual lock-down on the brain's sensory and perceptual systems.
One solution is suggested in the emotional regulation paper below. Just deadening or suppressing emotions often has a cognitive toll on memory, but in the figure below, analyzing was an alternative possibility. When people were told to analyze emotional film scenes as if they were an clinical observer - like a doctor- they weren't forgetful like the emotional suppression group, and they even recalled more than controls on tests of nonverbal memory.
Don't look to suppress, look to understand...
Privileged Status of Emotions
Anxiety, Happy Face Reading, and fMRI