First of all, grilled onions do not come from an animal. Also, I'd appreciate a little less pressure to put Thousand Island dressing on that shit. That is the worst dressing ever made. I would put raspberry vinaigrette on a burger before I'd consider that nonsense. Besides, that there is a "right" way to order is your first indication that you're dealing with an overrated sandwich.
There are burger places in this world that are so confident in their wares that they expressly prohibit customers from making any special requests. Extra onions? Nope. Hold the garlic pesto mayo? Hold your tongue, you heathen. Don't get me wrong, I hate that shit, too, but at least places like that earn their reputation based on the quality of the food, as opposed to the amount of prep time and detective work it takes to place a palatable order.
Speaking of that, what's with all the secrecy around the menu? If an item is available for the ordering, goddamn tell us. I shouldn't have to consult Snopes to make sure that what I'm ordering actually exists. That shit should just be on the menu where I can order it.
Then again, why do they have a fucking menu at all? From every report I've seen or heard, you can kind of walk into In-N-Out and ask for just about anything and they'll make it for you. Someone ordered a burger with 100 patties once and they made it without question. If you ask me, a business that adheres to "the customer is always right" with that much vigor probably has some kind of ulterior motive.
Also, they don't have bacon. Not on their real menu, and not on that secret menu that people love so much. Does the Internet know this? I personally feel like a lot of false In-N-Out fandom would be destroyed if this glaring lack of available salty pork was a fact more people knew about. There should be laws on the books that force burger joints to serve bacon. It is a vital part of the experience. Even if you don't initially order bacon on your burger, it's at least nice knowing there's some around if the taste goes south halfway through and you have to call in reinforcements. This is not an option at In-N-Out Burger, and that alone should be enough to remove it from contention for the title of America's best burger restaurant.