Always Be Learning
I worked with a very smart waiter once, well, at least she thought she was. I had just spent about a week creating a social network for our restaurant, on my own time, unpaid. I had taken the entire menu, and created an online, fully interactive version of it that any of my coworkers could access. This waiter approached me before our shift and said, "I would never use the site you created. I have a photographic memory, and I simply don't need something like that. Besides, when I'm not at work, this is the last place I want to be thinking about."
You will never know it all. A restaurant is a dynamic environment, with hundreds of ingredients and moving parts. Get off your high horse and embrace the fact that you are and will always be learning something new. Whether its the history of a single malt scotch, or the nuances of a grass-fed steak, there are infinite levels of information to be digested and reworked into language you can use table side. Don't be a know-it-all, be a learn-it-all.