job security n.

When some piece of code is written in a particularly obscure fashion, and no good reason (such as time or space optimization) can be discovered, it is often said that the programmer was attempting to increase his job security (i.e., by making himself indispensable for maintenance). This sour joke seldom has to be said in full; if two hackers are looking over some code together and one points at a section and says "job security", the other one may just nod.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.