Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it.

An effective way to test code is to exercise it at its natural boundaries

If you're as clever as you can be when you write it, how will you ever debug it?

Don't document bad code - rewrite it.

90% of the functionality delivered now is better than 100% delivered never.

Believe the terrain, not the map

Trying to outsmart a compiler defeats much of the purpose of using one.