Forgetting to add salt to the dough
Salt is a necessary component of all bread doughs. There are several reasons why you should add salt to the dough, according to the Weekend Bakery. The first is that salt enhances the flavors of other ingredients; this is especially true for focaccia flavored with herbs, olives, and other vegetables. The chemical structure of the salt also aids in the formation of strong gluten structures in the bread, resulting in a more elastic, chewy dough. When the bread is proofing, the salt will hold the carbon dioxide in the dough rather than allowing it to escape into the atmosphere, resulting in a soft and fluffy dough rather than a crisp cracker.
When adding salt to your focaccia dough, the only precaution you should take is not to leave the salt directly on top of the yeast for extended periods of time (as the salt will kill the yeast). If you mix the dough right away, you can be confident that the yeast and salt will coexist and collaborate to help you achieve a good bake.