Excel requires an internet connection

I've seen Microsoft Office 2010 do many bad, and even stupid, things. But this one really tops them all:

Right, so I can't open Excel 2010 because there's something wrong with the internet connection (or so it thinks - I'm actually writing this blog post so I have no idea what Excel smoked). But seriously, why the hell does Excel need the internet to open a spreadsheet?

Downloading Microsoft Office?? Dude, it's installed on my machine.

This is the single most annoying 'feature' I have ever encountered in a piece of software. A close second is having to open Excel twice, because it doesn't open the spreadsheet I double-clicked, the first time.

A new category of facepalm needs to be invented for Microsoft. The silly bugs encountered in LibreOffice are nothing in comparison. Goodbye, MS Office. Hello, LibreOffice.