I've got a fair idea why it is at the comic book shop I'm often asked if I work there. There's this comic book shop in a mall that's not really so conveniently located anymore, but was pretty near perfectly suited to my parents' old home, and I still end up going there as there's an Apple Store and various other interesting things, including a whole other Barnes and Noble with marginally different books on display than the nearby one or the next-nearest one. And in the mall is a small comic book shop that breaks some of the Comic Shop Rules for Commercial Dismalness by having a wide-open front in a fairly busy section of the mall (opposite the center balcony from the food court) and not having faded, dusty posters for Voluptina, Demon-Princess of Improbable Poses #1 Special Collectors Edition (by Frank Miller) covering the walls. But they hew to some of the traditional elements for comic shops, particularly the staff hiding away like chipmunks and only emerging when they feel comfortable, when there's been no motion from suspicious customer-like entities for several minutes or when one of the customer-things holds out a handful of cashew nuts.
So it's natural that innocent by-shoppers would turn to me as a guy who probably works there. If you saw a picture of me you'd agree: I'm tall, but pretty doughy, with a beard that loses its neatness about 120 hours after I leave the barber shop, and hair combed in a fashion that suggests an armistice of fatigue arranged among my hair, my shampoo, and my comb. I even go out in sweatpants, not because I don't care how I look but because I don't wear jeans and dress slacks are inappropriate for hanging out in the mall. In short, despite some differences, I look like I'm the guy being caricatured by the existence of Comic Book Guy.
Going up to me for help is, therefore, a very good strategy, and while I don't actually work there I do try to give a good impression and answer questions to the extent that I know anything. Questions about where some type of thing, like Archie comics or toy merchandise, are I can answer; questions about stock, not so much. While I really like the idea, at least, of comic books I haven't found books that I feel enthusiastic enough to buy regularly in years. The last books I collected regularly were the Marvel New Universe, about twenty years ago, which makes me kind of the guy who collects Go-Bots in a Transformers world. Mostly I go in to the store, look around, and eventually leave. I'm nearly as good a comic book fan as I am a modern science fiction fan.
Trivia: Captain America was the first Marvel (or Timely, depending on how you want to count the corporate names) comics character to debut in his own title. Source: Tales to Astonish: Jack Kirby, Stan Lee, and the American Comic Book Revolution, Ronin Ro.
Currently Reading: Alone Against Tomorrow, Harlan Ellison. (I got it in a used bookstore about six months ago and just got around to it. It was published back when Apollo 16 was being planned.)