I haven't dared pressing F1 for a long time now but I remember Visual Studio versions where pressing F1 would completely stop your computer because it starts up the "Help Server", lots of 7200 spinning rust churn, more churn, an Electron-style app opens..
That would be VS 2010 and later. Before that, it had an actual working offline help system (which took, IIRC, more than half of those CDs that came in the box). And that help was actually pretty good.
