F1 is actually my worse enemy, too close to F2 for my fat fingers.

The offline help is fine for Excel functions. But where I work, 90% of the functions used are coming from addins, and even though they also have a documentation somewhere, it can't be reached with F1.

Documentation is necessary but hints should be inline/contextual, like intellisense in visual studio. I don't want to have to leave what I am doing just to figure out which is the next argument in a function.

Excel could use a powerful autocomplete like intellisense that gives you basic documentation inside the auto-complete.

But Office is the "sleeping beauty" of Microsoft. A bit of an old and hairy beauty though.

Rarely does F1 work (like it used to) in most any MS app I've used in the last 5 years. I think they decided to just say fuck it and outsource that functionality to Google.

F1 works incredibly well in Visual Studio, especially if you're working with one of the flagship .NET languages. For example, highlight a core language element in your code, press F1 and you'll get specific help on it.