Unwritten rules

The biggest problem I have with technology today is there are too many unwritten rules of when and where you can and cannot use technology. Like in some situations it is completely acceptable, but if you are talking to the wrong person it is one of the worse things you can do to them. This would be fine if the rules would be across the board, but they are all subjective to the individual. Like for example i have a friend that is always on his phone, he finds that fine and not disrespectful, but my other friend finds that completely rude and finds him overall mean for that. So all of these are opinions and are not across the board. This would make this easier for some, because they would mot be put in my situation, where I do not know when it is fine so I just never use my phone.  I hate this too, but there is really no authority when it comes to this because, if someone says it is okay. Someone can just say no it is not. I just do not know, does anyone else have this problem.