Excel becomes a tool where people without a solid grasp of it use it for _everything_, at times mutating data without knowing it.

In the DE space, Excel is the bane of my existence. Some examples of messes we are asked to unravel:

* Cut and paste errors are too easy, once had an an executive boardroom meeting get derailed because one of the execs transposed a column header without realizing it.

* "Who has the most recent file?" becomes a cat and mouse game that sometimes does not have a single answer.

* Just yesterday I dealt with a "business critical" issue where a workbook with >300K VLOOKUPS caused the workbook to become unusable on common workstations - recalc times (with multithreading on) were excessive.

These are common stories, but my biggest issue is reproducibility. Understanding how data arrived at its current state can be impossible, and non/semi technical business users are often not held accountable for an audit trail. At times, Excel being an option is why we don't build more robust solutions, Excel is the gateway drug to failure.

"Spreadsheet" sometimes equates to "a mess", where "data frame" equates to sanity. Reforming the concept of a spreadsheet is a noble goal, but perhaps there is too much history to overcome.