The latest research on unconscious mental processing shows that people receive 40 billion sensory inputs every second, and we are conciuosly aware of 40 at anyone time.
Memory is easily disrupted.
You can store concrete words(table, chair) in long term memory more easily than abstract words(justice, democracy).
When you're sad o remember sad things. You cant remember much before age 3. You can remember things that you see better than words.