everything. Don't you ever need an uninterrupted block of time or don't you sometimes have a preference between two times that are ostensibly open (e.g. meet in the p.m. because you want to save your a.m. energy for something?) Also, even if you box out times you plan to do uninterrupted work, it's only natural that some of them could be shifted if the need arises.

I'm just saying that the calendar doesn't always capture everything that matters. Sometimes people have soft preferences or needs.