Like notaries, witnesses aren't generally required in order for a contract to be legally enforceable. However, each state may require special kinds of contracts (e.g., real estate deals, wills, and marriage agreements) to be witnessed by a third party in order to be binding.
McDonald's, apparently, use red and yellow because red=fast and yellow=hunger (hence fast food!). Remember also that meaning is what we create. It does not exist in the color itself and individual meanings may or may not exist in different cultures and individuals.
This sets how detailed you want the images in the game to look. There are two options - Fast and Fancy. Fast makes the game run faster at the expense of the way it looks, while Fancy gives you a better looking game at the expense of how fast it runs. The Fancy setting probably isn't worth the performance cost. To give you an idea, the image on the left is set to Fast and the one on the right is Fancy: