Why do systems I understand alone confuse me once they connect?

You can read one system well. Give you the parts, you find the pattern. But put two or three of your systems in a room together, and you freeze. You go looking for the single cause, the way you always have, and it isn't there. This is not a sign you've hit your limit. It's a sign you're using a tool built for the wrong job. A single system has a center. An interacting one does not. The trouble lives in the handoffs — where your part meets someone else's, where your team's output becomes another team's input. No one person holds that whole picture. That is not a flaw in you. It is the nature of the thing. So the work changes. Alone, you study. Together, you trace. You and the people beside you must say out loud where your systems touch, and watch what happens at each seam. The answer was never going to come from inside your own head. Stop searching there.