It makes sense to want to know the "why".
It makes just as much sense that your boss doesn't have time to explain that every time. Her taking the time to explain that costs the company time and money when both you and your boss could be getting something else done. Worry less about the "why" on the deadline and worryvmore about what specific scenario is happening at home w your kids one day or another day. Work extra hours when your family has nothing going on. Go home early for a date w your wife every couple of weeks. Go home early for one of your kids events every couple of weeks. Maybe pick one day a week to stay later than every one else. Then they will see that you are putting in extra time. My Domino's manager when I was in school said, "There's a time to lean and a time to clean".
Be efficient and figure out when those times are without having to consult your boss. (If you have that flexibility.) Be there for your family when they need you. When they don't need you, get your extra work in and earn your bonus, or find a different job.