I have known several people with this attitude. "I can't cook," they say, while making Kraft macaroni and cheese from a box. "Will you teach me?"
So you go into the kitchen and try valiantly to show them how to make real macaroni and cheese. And they take one look at you measuring out the flour and butter for the white sauce and say, "that's too hard," or "but you just know how," or "but how do you make it work?" And you put the whisk into their hand and tell them to whisk until the butter and flour combine, that this is called a roux, that it will be the base of your sauce, that flour helps thicken things. They take the whisk and sort of stand there, holding the pot handle, stirring gingerly until the flour and butter are at least tentatively mixed. "Ok," you say, "now whisk in the milk." "But how do I know how much milk to add?" they say, or, "how can I add it and keep whisking?"
They forget that they were making mac and cheez before, perfectly confident of their ability to stir two things together. They get defensive. They get frustrated. They get angry. Then they give up. "I can't learn to cook," they say. They don't realize that cooking is a process, or a craft. You can't just read a book and suddenly become a kitchen whiz; neither can you whip up a perfect pie crust on your first try. Those people who get frustrated and give up--no, they can't cook right then. They can't cook because they refuse to practice. So how do you learn to cook? You just cook, and see what happens.
Often, intimidating cooks--you know, people who produce fantastic souffles at the drop of a hat, or who throw bunches of seemingly random things into a pot and come up with an amazing soup--have been cooking their entire lives. They may have grown up in the kitchen, watching their mother make dinner, helping press hamburgers together and steam vegetables as soon as they were old enough to touch the stove. Years of experience make them confident. They know complex techniques because they have seen and practiced them over and over. They have no problem throwing strange ingredients together and seeing what happens because they have done it so often before. They feel at home and relaxed. They don't worry too much about screwing up; if they come up with something fantastic, great, but if they don't, oh well.
Thus, learning to cook is much like learning to be in the kitchen. Relax--the food isn't going to bite you, and it's no big deal if you mess something up. Try hanging out with your friends while they cook something. Ask what you can help with. Watch what they do, and ask why they do it. Pay attention to the cooking process, and eventually you will see how and why the ingredients work together. Get familiar with different foods and their cooking techniques. Then start to get comfortable with your individual cooking skills by following some simple recipes.
Measuring, stirring, chopping vegetables, cracking eggs--these are not that hard. You probably know how to do all of them already. If you don't, they only take a moment to learn. More advanced things, such as kneading dough, might take a little time to learn. This does not mean you can't learn them, however; it just means that you have to practice. Most cookbooks will have a technique section, so you can look up any process you don't understand. Or you can ask a friend (or your mom, who generally knows Everything about cooking) to help. Do NOT give up if your first recipe turns out badly. Resist the urge to throw down your spoon and storm out of the kitchen. Everyone's first recipe turned out badly, I guarantee. Just laugh it off and try something else.
Remember also that lots of foods can handle mistakes. Most dishes requiring chopped vegetables, for instance, will not suffer if you accidentally chop them either too small or too large. If you are making spaghetti sauce, and you add too much basil, you can add some more spices and tomato sauce to balance it out. Or you can see what a basil-heavy sauce is like; you might like it. For some recipes, like soups, you can add ingredients in any order. Then if you forget something, you can just throw it in later: the whole soup is not ruined. Meats can be marinated for any amount of time; the flavor will just be stronger if you forget about it for a while. Don't panic if you do something wrong: you can most likely fix it. The main exception to this rule is baking. I would not expect perfect results if you accidentally leave out (or double) the baking soda in a batch of cookies. I would also not recommend trying to knead the sugar you forgot into a dough that's already been in the oven five minutes (I did do this once). And pay attention to things in the oven: another thing you cannot fix is burnt food.
But don't give up. Read the recipe. Experiment. Pay attention. Keep going, and you will learn to cook.