Salt
For lunch today I had pizza from on campus, and the crust was made with almost no salt. It's a common mistake I've made baking bread over the years. I remember the first time I learned what salt does in bread. I made this incredible Italian artisanal loaf that took many days. When it was finally time to eat it, my wife had the first bite and told me something was wrong. "Did you put any salt in this?" I tasted it and the experience was not unlike taking a person who is used to living among the mountains down to the prairies: you are surrounded by wheat and nothing else.
I have a technique I use now to avoid this issue again. Part of the problem is that the way I make bread, you have to add the salt at a particular moment, and that moment is not near the beginning. You want the salt to add flavour, and also to slow the yeast, but it must be done at the precise moment. And, you rarely need more than 1/2 to 3/4 of a teaspoon. It always amazes me how little you need, but how significant it is in the end. I always measure the salt and put it with my bread start, carefully moving it through each of the early stages beside the dough, until it is finally time to add it. I've never forgotten to do it again.
What I love about bread is that it is nothing more than flour, yeast, water, salt, and time. You can't pare it back any further.