Usually, my problems with ingredients are either one of two things: either I run out of it or I rarely carry something because its never used in my kitchen.
There is, in my mind, a consensus among most people who cook or bake heavily that if you are going to make something, you should try to cook it from scratch as much as possible.
You know that horrible feeling. That moment when you realize you (or your partner or roommate or child) forgot to take something out of the fridge for dinner.