When there is no type hierarchy you don't have to manage the type hierarchy.

There's no such thing as a simple cache bug.

Rule 1. You can't tell where a program is going to spend its time. Bottlenecks occur in surprising places, so don't try to second guess and put in a speed hack until you've proven that's where the bottleneck is

Narrowness of experience leads to narrowness of imagination

Productivity is most important by engineering management rules, but enjoyment is most important for engineers. One stems from the other.

Fancy algorithms are slow when N is small, and N is usually small.

Data dominates. If you've chosen the right data structures and organized things well, the algorithms will almost always be self-evident. Data structures, not algorithms, are central to programming.