Earlier quoted context omitted.
Excel loads in ~1 second...and doesn't have UI lag after it does. Try working with large data sets in Google Docs and you'll have that 2-3 second lag time with _every_ operation you perform.
On the flip side, the new Windows "Metro" style calculator app takes several seconds to load ... and is less usable than the old calc.exe.
https://news.ycombinator.com/item?id=10791667
(Note that the "Calculator Plus" mentioned there has --- not suprisingly(!?) --- disappeared from Microsoft's download center, but you can still find the official, signed installer by searching for "CalcPlus.msi".)