Comment by lo_zamoyski

Children have the nice effect of cutting the fat out of your day. When you don't have children, it is very easy for most people to piss away their time on social media, reading useless news (99% of it is sensational dreck at the level of gossip), and so on. Children remind you that time is a very limited resource. Parkinson's law. You have less time, so your use that time more intensely meaningfully. I am willing to bet that much of the problems with focus and mental illness (rumination and all that) that people report would be resolved by taking on more responsibility. The knowledge that you don't have time to fritter away on garbage is enough to mobilize, organize, prioritize, and motivate you, dashing any temptations or even desires to indulge in worthless things. It's the same reason why people suddenly become motivated closer to a deadline or expected delivery date. Nothing focuses the mind more intensely than immanent death.