There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult.
The Law of Leaky Abstractions: All non-trivial abstractions, to some degree, are leaky.
There are only two hard things in Computer Science: cache invalidation and naming things.
programming is all about managing complexity.