Its creepy as hell when you are having a conversation with your SO in the car about [insert random products here], and then in about a hour when you open your phones or laptops at home you are bombarded with ads for said product's.
This happeneds all the time. Try talking about getting a new top load washing machine and mention it three times within ten minutes. Or try talking about getting a new lawnmower, but the trick is to say it three times within ten minutes or so.
When I go for a bike ride with my SO we always ride side by side on streets that have a posted limit at or below 40kmh.
We usually only ride side by side on residential streets. Occasionally we get someone driving too close to us when passing or shouting out their windows saying single file in the same way.
Its like going for a walk, we would not walk in a single file, neither would we sit in a car in single file.