You can't tell people anything (2004)
I firmly believe this is almost exclusively a didactic issue, ie. the person explaining does not or cannot reflect what is common knowledge and what needs to be explained in addition to the new ideas.<p>This comment resonated with me so much<p>"I’ve been on the receiving side of this before. What typically happens is the Dunning-Krueger Effect. This is typically understood as incompetent people are too incompetent to determine that they are incompetent, but its lesser-known corollary is that competent people assume everyone else is competent too, and thus they don’t have to explain themselves.<p>Once you understand this, the reason for poor communication becomes clear. The team doesn’t bother to explain their presumptions, falsely assuming that everyone is on the same page. They feel free to use original concepts they developed, internal team slang, unexplained acronyms, etc. Then they’re baffled why people are so stupid and can’t understand their outstanding presentation that obviously went over all the details. "<p>I, too, have been on the receiving end of such treatment multiple times. 
I wouldn't call exclusive or inside knowledge "competence". What shocks and baffles me is exactly this phenomenon: Companies have inside knowledge, which an outsider starting fresh could not possibly know. An outsider also has a really hard time grasping and sorting the new inside information. Yet, it is common of engineers to not reflect at all about "what can this person know and understand without working here 5+ years", and prematurely jump to conclusions that outsiders are slow, and they are lazy to not aquire this information on their own.
This behavior is not competent, or smart if you ask me.<p>When you try to communicate the issue at hand, it might also fall on deaf ears, because reflecting about such meta levels of knowledge is a skill not everyone posesses and could easily understand.
In the end, either side, the insider and the outsider, can experience a lot of frustration, because their viewpoint is so incompatible with the other.