I turn 42 later this year, and this would explain a lot. Not in terms of me being unable to be super-efficient and productive, but just in terms of seeing connections everywhere.
In a systematic review recently published in the journal Psychophysiology, researchers from Monash University in Australia swept through the scientific literature, seeking to summarize how the connectivity of the human brain changes over our lifetimes. The gathered evidence suggests that in the fifth decade of life (that is, after a person turns 40), the brain starts to undergo a radical “rewiring” that results in diverse networks becoming more integrated and connected over the ensuing decades, with accompanying effects on cognition.
Source: The brain undergoes a great "rewiring" after age 40 | Big Think
Early on, in our teenage and young adult years, the brain seems to have numerous, partitioned networks with high levels of inner connectivity, reflecting the ability for specialized processing to occur. That makes sense, as this is the time when we are learning how to play sports, speak languages, and develop talents. Around our mid-40s, however, that starts to change. Instead, the brain begins becoming less connected within those separate networks and more connected globally across networks. By the time we reach our 80s, the brain tends to be less regionally specialized and instead broadly connected and integrated.
“During the early years of life, there is a rapid organization of functional brain networks. A further refinement of the functional networks then takes place until around the third and fourth decade of life. A multi-faceted interplay of potentially harmful and compensatory changes can follow in aging,” the reviewers concluded.