[AnimalMuppet]

This one is wrong. The Law of Leaky Abstractions is in fact not a lie. All abstractions actually do leak.

People take that as an excuse to be sloppy, which it isn't. You should do the best you can to make non-leaky abstractions. When you have done so, you should look for the leaks, and do your best to plug them. After that, you should do so again. You should really try to make it as solid as you can.

But it will still leak. It will be less garbage than much of what we have to build on, because of the effort you put into making it better. But it will still leak.