You've been with at least 5 startups in 9 years. That suggests to me that none of them were terribly successful, in which case I suppose just about any problem could wait til Monday.
My startup has almost 20,000 paying customers and if something goes wrong, you bet your ass I'm on it immediately, whether it's 3am and I had more than few drinks earlier that evening, or I'm in Hawaii on my birthday and 7 servers lose power and I have to spend the next 5 hours dealing with that mess. Did I mention it was my birthday and I was in Hawaii?
These scenarios are rare, but they do happen. I would never actually take my laptop to a restaurant, but if something bad happens it needs to be dealt with pronto. In the example from the story, I would have either delayed going out, or if it happened when I was already out, then I would leave as soon as possible. In general I don't put work before family or fun but every once in a while you have to if you want to run a successful business.