We recently build spreadsheet support in our app. Our pain-points are almost entierly mundane: * Macro-enabled Excel files, that can only be run on or by Wind

We recently build spreadsheet support in our app. Our pain-points are almost entierly mundane: * Macro-enabled Excel files, that can only be run on or by Windows. * A endless log of Excel files that have errors. Most of these are files that are not compliant to the spec, but have been supported by various software over the years. * User creating formats and overly complicated/brittle spreadsheet.