Stanford researchers asked students to walk around campus wearing a silly advertising sandwich board. Those who agreed estimated 62% of peers would agree too; those who refused figured 67% would refuse. Each side saw its own choice as the normal one. It's called the false consensus effect, and it explains a lot of mutual bafflement.
Remembering is not replaying a recording — it is rebuilding. Each time you recall a memory, it becomes temporarily malleable and can be altered before being stored again. That is why two people can sincerely remember the same event… differently.
In 2003, Johnson and Goldstein compared European countries. Where you must tick a box to become a donor, consent rates ranged from 4% to 28%. Where you're a donor by default unless you opt out, they topped 85%. People aren't more generous on one side; most simply stick with whatever option was chosen for them.