Mindspeak
With long distance ability in mindspeak and virtually everyone on the same channel, can you imagine how noisy it is? It must be a lot like trying to listen to one one voice in a crowd. Proximity makes it easier, but there can still be an enormous amount of interference. The more people centered in a particular location the worse it must be. One voice whispering in your head all the time is probably bad enough, I cannot imagine lots of them. It makes you appreciate the idea of building shields to block out the mental static and forcing people to knock in order to get your attention.