Learning French is trivial: the word for horse is cheval, and everything else follows in the same way.
One man's constant is another man's variable.
One can't proceed from the informal to the formal by formal means.
Don't have good ideas if you aren't willing to be responsible for them.
You think you KNOW when you learn, are more sure when you can write, even more when you can teach, but certain when you can program.
The best book on programming for the layman is Alice in Wonderland, but that's because it's the best book on anything for the layman.