COPY-PASTE VISIBLE CELLS ONLY
A typical painful situation in Excel is when you are working with a filtered set of data, and you want to copy data from one column to another.
If you just try to copy-paste on your own, Excel will ignore the filter and the pasted data will apply to some of the hidden rows. Then you are left with a corrupt set of data.
Power-user offers a tool that will get you out of this situation very easily. You can simply copy only the selected visible cells of a column, and paste them only in the selected visible cells of another column.
This will save you time and protect the integrity of your data.