One pillar of the scientific method is reproducibility, that is, being able to redo an experiment and get the same result. Sometimes this is very hard to accomplish. For example, if you’re doing field work, you might end up collecting some very rare samples or observe a rare natural event. If you work in the lab, tracking all the variables that go into an experiment and might influence it (e.g. the way a person pipettes or mixes reagents) is similar to following your mom’s recipes… most of the times it doesn’t give you the same amazing dish.
However, when analyzing data on a computer you would expect to have control of all the variables and be able to re-run everything you did at the touch of a button. Right? Well… it’s complicated.