Openoffice does this too, and the worst part is that it will take something and interpret it as a date, but then you force it to interpret it as a number, instead of using the number you typed it will use the index number of the date which is a completely different and useless value.

In short, it takes the number you put in and converts it into a date against your will, and you can't change it back. It would be like if you typed in "sunshine" and it interpreted that as the temperature of a sunbeam and put that in the cell instead of the fucking thing you typed. So annoying!!

Another minor gripe is how their Pi() uses enough digits that it lands on a 5 and rounds up, which breaks all sorts of sine math. If they had rounded down or added/removed a digit of pi that wouldn't be an issue. I have to intentionally add error to my functions just so they work. On the up side I was able to provide mathematical proof that the human tendency to round up at 5 is at odds with the real world. It makes more sense to round down, though I always just add/remove a decimal point so I don't have add arbitrary information to the system by always assuming a roundup or rounddown. If I'm forced to end at a 5, I round down, which is at odds with how people do it but it breaks less.

EDIT: come to think of it, it makes a lot of sense for 5 to be a round-down situation. If a particle has just enough energy to jump to the next state but no extra, it would be far more likely to stay in its current energy state than it would be to expend energy to make that jump. Even an infinitesimally small increase over the exact amount required to make a jump would give it that necessary kick to actually make the jump.