While following this thread with interest, there having been some constructive posts, I am disappointed we seem to have accepted an implicit assumption that comics professionals must be polite for that tag to fit them. Strictly, where do good manners come into it, beyond an ability to co-exist with people the pro has to deal with to get the job done?
Charm, patience, purity of spirit and such are ideal, certainly. They probably won't hurt sales. But if Pro X prefers to growl at fans from a cave in the woods, we maybe should just take note not to attempt feeding or poking with sticks. Is the work any good, is the important question. Or, turning it around: how often do creators keep their jobs, just by being nice? (Let's keep this moderately non-libelous, folks. <g>

A medium rep for truculence can even confer a weird benefit, much as dangerous animals draw crowds eager to see who'll get the next mauling.