I think my buddy James Cullen put it pretty well: Conventions are like DeviantArt in real life. Everyone’s free to browse, a select few sell anything at a profit, and you’re surrounded by bizarre things you can’t unsee. The difference, I would argue, is that conventions are an experience worth having, and that most of the artists there are actually decent at what they do. It’s partially because there’s less space for the crap to filter into, but mostly because you have to pay to sell anything there.
But John did nail it otherwise, despite being Irish.