In Coders At Work (http://www.codersatwork.com), Ken Thompson says, "When I was 30, 35 years old, I knew, in a deep sense, every line of code I ever wrote. I’d write a program during the day, and at night I’d sit there and walk through it line by line and find bugs. I’d go back the next day and, sure enough, it would be wrong."

Building things without deep understanding may produce a program, but it won't get you to A. Building understanding gets you to A. This is a deliberate process that takes time and work. You may not get all the way to A, but it will put you on the right path.