Asking 'are you mad at me?' when he's just busy
This is the one almost every woman has done, and it costs more than it seems in the moment. A man who hasn't replied in four hours during a work day is almost certainly busy. The message 'are you mad at me?' arrives and suddenly he has two problems: the work problem he was dealing with, and now the need to manage your uncertainty about the relationship. It's a small tax, the first time. By the tenth time, it has become the defining quality of the dynamic. The deeper issue is what the question signals: that you interpret his silence as evidence of something wrong, which means you're monitoring the relationship for signs of damage at a level that makes ordinary quiet uncomfortable. A man with a busy day doesn't want to come back to a paragraph about the silence. He wants to come back to lightness — to someone who assumed everything was fine because there was no reason to assume otherwise. Let him be busy. He'll come back.