Why might cookies come out too thin after baking?

Cookies that come out too thin after baking can typically be attributed to the condition of the dough and its ingredients. When the dough is too warm or not sufficiently chilled, it can lead to the fat (butter) melting too quickly in the oven. This rapid melting causes the cookies to spread out more than intended during baking, resulting in a thinner shape. Additionally, if there is not enough flour in the dough, there isn't sufficient structure to support the cookie as it bakes, leading to a further spread. Thus, both the temperature of the dough and the amount of flour play crucial roles in determining the thickness and structure of the final cookie.

In contrast, having too much sugar may contribute to spread as well, but it is primarily the temperature and the balance of flour that are the key factors here. Similarly, too little butter might lead to denser cookies rather than affecting their thinness. Lastly, while incorrect baking temperature can influence the final product's texture, it does not directly address the specific combination of warmth and flour balance, which are critical in this situation.