To steal pears without intending to sell or eat them is not only immoral, but hard to understand. To kill a rich and annoying uncle is easier to understand, but morally worse. And of course serial killers commit crimes that are both hard to understand and morally bad. The two dimensions, thus, appear to diverge.
Notice an interesting asymmetry between the morally good and the immoral. A morally good action may excite wonder, but it is not that hard to understand. It is only the immoral and the neutral action that can be really hard to understand.
A third dimension, which I indicated in an earlier post, is the degree to which the deed is reflective of a bad character. This dimension is to some degree independent of the preceding two. It is equally understandable why someone might kill for money or to defend a friend's honor in a duel, but the former reflects a more vicious character. Tormenting an invertebrate is less bad than killing to defend a friend's honor, but more reflective of a vicious character.
The dimensions are not entirely independent, however.