[mikekchar]

Actually the number of opportunities you have to build something from top to bottom are not that numerous. In my 30 years I can think of 4 non-trivial projects off the top of my head. In fact I often advise programmers to have a side project where they get to make all the decisions and see how it works (or doesn't). One of the side benefits is that it tends to make people much less "my way or the highway" at work because they have somewhere that they can express themselves fully.

[spacemanmatt]

I have been recommending side projects on a similar basis for a while. I usually emphasize learning under the condition of leisure rather than schedule pressure, to enhance focus on good design and allow for a depth-first learning style.