I deal with this fear by offering fandoms with no existing fic; that way at least I know my offering is better than all available alternatives :-). And also by reminding myself that everyone who participates in Yuletide wins, because they get 2,000 lovely stories to read. I like getting a story just for me, but even if it isn't perfect, I'll find something else that is that I didn't even know I wanted.

I am impressed you can do big bangs, though. I need exchange-based ficathons to make me feel like the deadlines actually have teeth. Prompt-based or big bang or whatever, I tend to just blow off when I get distracted by something new and shiny.

(And seriously. They will not hate it.)