That and, well, video that's on by default. I know this somewhat paradoxical because we're talking about _video_ conferencing tools but in many cases seeing the

That and, well, video that's on by default. I know this somewhat paradoxical because we're talking about _video_ conferencing tools but in many cases seeing the other participants isn't as important as hearing them clearly or viewing a shared screen. A video stream can take a lot of the available bandwidth, at the expense of those other channels.