With a little time, inexperienced and inefficent programmers can understand often understand the crappy code they wrote just fine. What they can't do is avoid

With a little time, inexperienced and inefficent programmers can understand often understand the crappy code they wrote just fine. What they can't do is avoid writting it in the first place. For most of them if you say great this works now make it better they will have zero understanding in what direction they should try and improve things.