I hate excel. For some reason, it has become the standard for creating any grid-based documents, even though the table support in word would often be far superior when equations aren't needed.

I hate the lack of smooth scrolling, especially when you have differing cell heights. I hate the lack of cell padding, leading to manually sizing every row.

Most of all, I hate the total lack of focus. What sort of document is it aimed at creating, these days? The answer is certainly not what is was 10–15 years ago, but the basic interface hasn't changed much (ribbon aside).