Guilty. The reason was living with abusive partner and not being brave enough to end the relationship. Things were bad, but not bad enough to do something about it.
This is just how I like to work and approach problem solving. I can take breaks when I make the effort, but, when work starts, I rarely think about anything except climbing whatever mountain I find myself on, helping others at my company, or exceeding my own (or others') expectations. That intensity helps me think deeply and solve problems effectively.
There are people in my company who do good work but draw boundaries clearly and sharply. I respect that. I just love what I do and find it interesting and absorbing partly because I love the intensity of striving and struggling, constantly refining, improving, growing, and exploring.
My company generously rewards good work, too. That also helps; my effort never feels wasted, unacknowledged, or unrewarded.
This seems quite distinct from what is discussed in this thread, which is people feeling some kind of pressure to work long hours, or to be available after work hours when they're supposed to be doing personal stuff. And, usually, the reasons for being called up don't seem to be some genuinely exciting problem that it feels invigorating to tackle. Instead, it's typically some form of TPS report that needs pushing around.
Where I work, a normal workday is 9 AM to 6 PM with an hour lunch. There's some flexibility as to the actual hours, I usually do 8-5, others do 10-7. Yet, some people always put in very long hours for some reason, complete with gulping down a sandwich in front of their computer for lunch. I'm not sure what gives them the impression they have to do it, since it's clearly not expected from our common higher-ups.