It is difficult for a maker not to add something to an artefact. Either unintentionally, through the way they work compared to other makers. Or intentionally, with thoughtful touches they think to add.
This individuality adds personality to the artefact. Audiences may find it charming, full of character, or quirky.
Often these characteristics are not needed: the artefact would be just as useful without them. But they often make it more enjoyable to view or use.