The Law of Leaky Abstractions explained by Joel Spolsky in the most real real-world examples. His example of TCP over IP demonstrates that even though TCP is supposed to completely hide IP and make sure that all transmission from one computer to another takes place reliably and the user is not even supposed to know about IP, sometimes the problems in IP leak through the abstraction and dont let TCP work. One of these situations being “your pet snake has chewed through the network cable leading to your computer”.