Look, don't touch
Had she taken the saying "Look, don't touch!“ more seriously, she would have spared herself the additional work.
A scientist saved experimental data on her computer. One day, she opened the original raw data in Microsoft Excel and the formatting of some columns was changed automatically. In doing so, the original values were permanently re-formatted and were lost for any further analyses. Since there was no additional copy of the raw data, the experiment had to be repeated.