Now, this one is a weird one, but everyone is guilty of it, even some professional chefs. Stirring. Everyone has been stirring stuff wrong for generations. If you have a large pot of something like stew, soup, or sauce, you probably stir in a circular motion, usually clockwise or counter-clockwise, right? Perhaps along the edge of the pot, or in a spiral, either going inward or outward?
Well, you're doing it wrong. When stirring, do in one of two manners: First, in small circles, working from the outside and going inward. Similar to how you might draw a cloud or petals on a flower. Or, stir in a figure-8 motion. This is especially useful if stirring in an oval or square-shaped container. Also, stir upwards. How? Angle your spoon so that basically, you're bringing the part of the food that's closest to the heat source, up to the surface, and vice versa. This allows for a quicker and more even heat distribution. Also helps to prevent burning.
I'm happy you got that passive/aggressive thought off your mind.. Cook on, big fella.
#6 Grocery store chills some vegetables but not others, I do what they do.
#9 Mix sauces similar to mixing paint; alternate top to bottom and outside edge inward.
#12 An accurate meat thermometer is a crucial tool. Learned my lesson after I overcooked a good piece of meat.