Non-contiguous columns
When someone sends me a spreadsheet that includes empty, headerless columns that they have shortened the width on for "formatting", I initiate the following sequence: 1) Print the document out 2) circle the headerless spots in red ink 3) Soak the document in desk-vodka 4) Tie it to a rock that is kept around for this specific purpose 5) set it ablaze 6) launch "tutorial" into offending cubicle 7) collect rock.
These 7 steps guarantee that spreadsheet integrity will be maintained in your organization. Excel tables are not for display, so don't put in headerless columns that you have shortened the width on in an attempt to "format" your document. Excel is a calculator, and non-contiguous data is generally not sorted together. Sometimes, Excel will sort all data columns together, but usually it counts the empty column as a break in the data. Then, when you go to sort a column, all of your rows become incorrect.
