Every morning when you leave the house, you push the button on the garage door remote closing the garage door. Then 10 minutes later, you can’t recall if you closed the garage door because you do the exact same action at the exact same time every morning, so they all blend together and you couldn’t tell if your memory was from that morning or any of the previous mornings where you went through the same motions like you have countless times before. You just experienced Repetitive Familiarity Amnesia.
When two people spend a lot of time together and begin to develop feelings for each other. But they actually are just assuming society's view on relationships. That people are suppose to be in pairs. So two good friends think they're in a romantic relationship.
John and Jane are both unemployed, so they have a lot of time to spend together. They start getting feelings that they mistaken as romance. They start really dating, get jobs and realize they were suffering from societal familiarity disorder (SFD)!