The thing is, before you have kids, which no one AFAIK ever tells you, is you completely take for granted the mental "downtime" of not having to worry about ano

The thing is, before you have kids, which no one AFAIK ever tells you, is you completely take for granted the mental "downtime" of not having to worry about another human being's safety and emotional health (e.g., your example to whit, you're just "sitting" at the game, but do you think your son would really like if you opened up your laptop and totally ignored him for 2 hours?). And the "emotional labor" isn't so much what you're _doing_ for your kid as much as being on constant mental alert yourself. Every minute that your kids are not asleep, you're keeping a spare eye and ear and the attendant mental energy on making sure they're reasonably safe and okay, and that's damn exhausting - even when they're sleeping, you can't go down as soundly, because they might wake up and need you. And those subconscious mental cycles you use to work on problems, the lack of time you just "sit down" when you wake up in the morning or finish breakfast or get home from work to decompress - not to mention the sleep deprivation - REALLY add up.