I can't draw skulls either

So my main pet peeve with tattoo artists is anatomic incorrectness. Look, if you are going to be a tattoo artist, you should, if only to suit the purposes of self-respect, learn to #$&@^%ing draw. So far, I've noticed two particular problem areas: breasts and skulls. Both are very popular in tatto art and both, apparently, require more knowlege of normal human anatomy than many tattoo artists possess.
With regard to either subject, you should look at a few before you attempt to draw them. You should also practice.
For my diagrams, sometimes I'll draw in the tattoos in rather than just describing them (if I'm just standing around waiting for my professor to show up, if I'm in the mood to draw anyway...)
Today's guy had a whole lot of skulls and they were all wrong. Every last stinking one. And not just a little: these were really funny-looking-- bumps where there are no bumps, teeth that don't look like teeth (think little picket fence), noses instead of little nose-holes...
So I'm muttering and drawing them in and finally take a look at my final product and, well, here's the problem with my skulls: they always look way too, well, cute. At least his skulls looked mean. Mine looked like he had a bunch of skeletonized hello kitty heads tattooed all over him (which, come to think of it, might be kind of cool...)

Here is a summary:

My skulls
Big, round eyes
Small, human teeth
Little, teardrop nose holes

His skulls
Big, frowning eyes with fake eyebrows
Small, square-ish, non-tooth objects
Sometimes actual noses, sometimes stuff that looks kind of like webbing