Selecting a column selects ~1048576 cells. This means any operation (accidentally or intentionally) performed to a column;

a) can take 10 minutes to perform (assuming Calc doesn't crash in the process, and depending on the document size)
b) can take 10 minutes to revert (assuming Calc doesn't crash in the process), and;
c) may unnecessarily load the file with data (I have noticed calc become unusually slow to operate, eg scroll through some files, before; perhaps this is related)

An example of this issue would be if the user must insert 10 new columns into a 100 column spreadsheet and copy and paste the first cell of each respective preceding column into the first cell of each new column. It is difficult to perform this operation quickly without copying and pasting the cell contents into an entire selected column (for at least one of the new columns).

To replicate the issue;
1. create new calc document
2. enter "hello" into A1
4. copy the cell A1 (Ctrl-C)
5. select column B (by left clicking on column header "B")
6. paste (Ctrl-V)

Some notes;
- when the text contents is copied (and not the cell itself), the issue only occurs when the cell being copied and pasted contains a formula
- the time to execute the operation scales linearly(?) with number of columns/text in the document. 
- it appears to spend most of its time "Adapt[ing] row height".
- sometimes Calc will crash when performing the operation (irrespective of the file size), and sometimes it will not.
- on Linux, the runtime crash (/near infinite loop) can be terminated by executing "killall soffice.bin" in the shell