Props to Facebook for having "2G" day. I hope it still happens.
* Dropbox is meant to have a LAN sync but fails back quickly to syncing from their servers. There's no way to debug why it isn't using other hosts on your LAN
* OneDrive has no LAN sync at all
* There's no way to debug Windows 10's LAN update sharing if it fails.
* Windows 10 will default to uploading partial updates to other users on the Internet (bittorrent style)
* Windows 10 will let you set a Wifi connection as "metered" and actually behave quite well (deferring updates, driver downloads and OneDrive data), but there's no way to set Ethernet networks as metered, outside of a registry hack.
* Google not supporting SD cards in the Nexus line (yes, I know about the performance issues, I own several >$50 SD cards that are trash). Mobile data is expensive.
* It took Google until 2016 to offer offline caching of YouTube videos, and even then you have to pay them for the privilege
* Microsoft's newer .NET and Powershell stuff download >50 megabytes of dependencies from NuGet.org and MyGet.org. Offline caching is possible, but maybe not on Linux