Swiping through more photos than you should
When someone hands over their phone so you can see pictures of their new dog, or their trip to Delaware, or whatever Gremlin-like creature they spotted on the subway that morning, there is a certain code of conduct that should be observed. And it is this: STOP SCROLLING WHEN THE CONTENT CLEARLY CHANGES.
Look. We're friends, but that does not give you license to swipe through my entire photo album. What I choose to privately share with my, uhhh, dermatologist is my business, thank you very much.