Because there is no shortcut for things learned over a period of time through trial and error. Your brain learns and makes judgements over time through experience and, the strange thing, what I feel is that it can alter new decisions it is making right now based on older memories to do something and that is totally logical as well. Without understanding what I am writing, just copy-pasting, I guess is going to make new developers horribly lazy, maybe. But then again, there are always two sides of the same coin.