You put your data into fancy libraries, algorithms etc., get some results out. You see some statistical properties of your data. So far so good. Are numbers alone enough, though?
English statistician Francis Anscombe, on very suggestive example, teaches us that you should use your eyes to additionally evaluate your data. In 1973 he presented four datasets with almost identical basic statistical properties.
Diagram taken from wikipedia:
Table, also taken from wikipedia:
For us, humans, this is very good news that our brain is still quite powerful computational wetware 🙂