To me, though, masks do not evoke a thrill of excitement or mystery so much as a rush of profound unease. With few exceptions (I don't mind Zorro's mask, for example, or Spiderman's for some reason), I simply don't like masks. In their hiding of the expressions that we use to connect with people, to read them as human beings, masks seem to cut off an essential element of humanity. And particularly with the kinds of masks associated with masquerades, as they are part of almost garish parties, masks appear so sinister as to be of Hell.
Because I finally get to respond to Irishlaw when she's not in political mode, and because she and the Fool have been having a back and forth on the topic, and because I like to write about the things I love, I figure I'll examine this in a bit more detail.
According to Irishlaw, her aversion to masks stems at least partially from the literary: she mentions the Phantom of the Opera, the horrible orgy scene in Eyes Wide Shut, and most prominently Poe's "The Cask of Amontillado" and "The Masque of the Red Death." But this is certainly unfair to masks as an art form: if New England's favorite manic depressive had turned his pen to writing about ice-cream and fluffy puppies, we'd be reading stories of frozen hellhounds. Poe's genius was the horrible and unsettling, and to blame masks for the nature of his madness seems more than a little harsh. 
In any event, perhaps Irishlaw's aversion is merely a lack of familiarity with some of the histories and traditions of mask-wearing. In the hopes of changing her mind just a little, I'm collecting a few of my favorite examples from the Italian here. (We'd be here all night if I started on Japanese noh masks or African ritual forms, and I won't even touch the Commedia del arte.) Far from being used to cut humanity from the man, masks have frequently played important roles in bringing people together.
(Note: some of the links below are to sites that aren't spectacularly authoritative: I don't know that many websites about such topics, so these are just Google hits. Anyone with better information can leave it below.)
The Mask as Tool: One of the most famous of the masks found in Italy wasn't originally used for disguise at all. The Plague Doctor's mask was worn by those who inspected the diseased and dying during the Black Death. The bottom of the extended 'beak' was filled with bags of herbs and perfume to ward of evil spirits. Certainly not as effective as it could be--they didn't know the plague was spread by rats and fleas--the mask remained a sign of what mercy could be given.
The Mask as Social Leveller: One particular use of the Venetian mask--particularly the volto-- was to allow members of different social orders to speak without hurting their standing. Much as certain bloggers find it convenient to hide their identity online in order to avoid conflicts of interest or keep separate their online and offline identities, such anonymity actually permitted communication that might otherwise not have occurred. Of course, they also permitted less laudable things--high-stakes gambling and excessive flirtation, for instance--such that Venetian law regarding mask-wearing became more and more strict.
The Mask for Romance: Of course, one of the reasons such crackdowns were necessary was that masks provided such opportunities for... moral mischief. (Indeed, the Venetians passed laws against wearing masks when visiting convents, to preserve their moral order.) One of the more interesting of these is the moretta. The small oval mask hid only the center of a woman's face, leaving much of its beauty available for view. Women held it in place by grasping a button between their teeth, leading to its nickname of muta. The game for men wishing to woo them was to entreat as best they could, their partner's responses hidden by the mask. Their only way of knowing if, at the end, they'd prevailed upon the lady was if she were willing to remove it.
There's much more, and I could go on for ages on the topic, but that should suffice to show that masks were not always for concealing emotions, hiding humanity, or providing one with an image of hell. As both Irishlaw and the Fool said, "A chacun, son goût," but if I ever do hold a masked event, I know one person I'll have to invite.
: Indeed, I'm not certain I agree with Irishlaw that the ghastliness of "The Cask of Amontillado" has anything to do with masks at all, especially their tendency to hide human emotion. While Montressor does indeed don a silk masque and roquelaire to go outside during carnival, he proceeds to his own home. While there is no mention of Fortunato or his murderer ever taking off the masks, there would be no reason to keep wearing them once indoors. On the other hand, the real horror of Montressor comes not from any work of silk, but from what he manages to hide in his face itself:
"Drink," I said, presenting him the wine. He raised it to his lips with a leer. He paused and nodded to me familiarly, while his bells jingled. "I drink," he said, "to the buried that repose around us." "And I to your long life." He again took my arm, and we proceeded. "These vaults," he said, "are extensive." "The Montresors," I replied, "were a great and numerous family." "I forget your arms." "A huge human foot d'or, in a field azure; the foot crushes a serpent rampant whose fangs are imbedded in the heel." "And the motto?" "Nemo me impune lacessit." "Good!" he said.
Montressor toasts to the long life of a man he's about to let starve in a crypt, coupling it with a reminder that for his family "No one provokes me with impunity." That portion of the story always struck me most deeply: the ability to hide one's feelings in the face of anger sufficient to inspire murder.