"Wait, it's crunch time and you're not sleeping under your desk as well?"
I felt a lot of resentment like they were leaving the 'kid' to do all the heroics. It didn't take me having kids to get it, it came much before that when someone I really respected had their first and they could basically tell me my future word for word. But I did get it, at least as much as you can pre-kids.
I've had some crunch times before where I practically didn't see my kids for four days because I was getting home late and leaving early- I can honestly still handle the physical toll. The mental toll is just something else. Now, if that's going on I still peel out for dinner and bed time and head back in to the office when they're all taken care of- then it's 'just' my wife getting neglected.
Your boat won't resent you, won't ask you where you've been, or be on the other end of FaceTime crying because they miss you when you've been on a work trip for a few days. Your boat doesn't depend on you for its survival on a minute by minute basis, and your mechanic doesn't need all the physical and emotional support you can muster (and probably more). Your kids and partner do.
Parents' lives aren't full, they're literally exploding with shit (often times quite literally) they have to deal with that makes work look like a freaking vacation. There's a huge emotional component to all of it that's practically unquantifiable, but suffice to say that if I'm feeling as if I've neglected my family for a few days, I may as well just pack my shit up and go home, because I'm not getting anything else actually done, even if my body and mind should still be good to go.
At the end of the day, we're agreeing to work for a determined price for a determined period of time. Now, at salary it gets fuzzy, and you hope that it all evens out, but in practice it won't unless you decide to make it so. Whether you have kids or not, you should be fighting to keep the balance- and any boss who can't accept that is a real jerk. We all love team players and rock stars, but it doesn't mean you also have to be a doormat and afraid.
I think the person we should all be looking up to is the person that is REALLY EFFING GOOD at what they do and also has a variety of interests and hobbies that are seemingly disconnected from the day job.