With the exception of skintight costumes and flowing capes, no item of apparel screams "superhero" (or "supervillain") like a mask. In fact, proto-superheroes like the Lone Ranger and Zorro were donning masks to hide their identities years before doing so became fashionable among the superhero set. Comic book masks provide not only anonymity but often protection or even special powers - not to mention that the right mask on the right hero can "strike terror into [the] hearts" of evildoers. Add the fact that masks just look cool, and it's easy to see why so many comic book characters sport one.
Of course, a case can be made that masks are often the most impractical and uncomfortable part of an already awkward ensemble for most heroes and villains. When fighting for your life against overwhelming odds with the fate of the universe at stake, one would think a pretty high premium would be placed on simple things like seeing, hearing, and breathing properly, but apparently, no one bothered to tell the characters on this list - because they wear the most uncomfortable masks in comic book history.