Law of leaky abstractions

All non-trivial abstractions, to some degree, are leaky. -- Joel Spolsky

In his article of "Law of Leaky Abstraction", Joel Spolsky claims that abstractions fail to a certain degree; sometimes a little, sometimes a lot. Thus, he coins the term "leakage".

Quoting one of his examples on TCP over IP:

TCP attempts to provide a complete abstraction [of providing realiable data transmission] of an underlying unreliable network [IP], but sometimes, the network leaks through the abstraction and you feel the things that the abstraction can't quite protect you from.

References

[The Law of Leaky Abstraction]