Appearance
As you have seen from the study sheet above a "nisse" is not capable of hiding his feelings. On the other hand he does not have the slightest intention or wish to do so either. If his mad he wants you to see it, if his sad, happy, sorry or pissed, he want you to see that as well.
In this manner they are completely different from us, who tend to hide most of out feelings, some of us are even unable to show them. Even the positive ones. Where a "nisse" is vain, boastful and sly, we humans may be the same but are taught not to show it. It is not considered the done thing.
Not so in the "nisse" world, oh no. If a "nisse" is happy with his clothes and appearance (and most of them are, believe me). Then they show it to the maximum. If he’s happy with something he has made with his hands (and most of them are that, too), he brags about it flashing the product too all and sundry.