Related:

• misbug /mis-buhg/ n. [MIT; rare (like its referent)] An unintended property of a program that turns out to be useful
  something that should have been a bug but turns out to be a feature....
• feature n. 1. [common] A good property or behavior (as of a program).
  Whether it was intended or not is immaterial. 2....
• chroedinbug: /shroh'din-buhg/ [MIT: from the Schroedinger's Cat thought-experiment in quantum physics] n.
  A design or implementation bug in a program that doesn't manifest until someone reading source or using the program in an unusual way notices that it never should have worked, at which point the program promptly stops working for everybody until fixed....
• miswart: /mis-wort/ [from {wart} by analogy with {misbug}] n.
  A {feature} that superficially appears to be a {wart} but has been determined to be the {Right Thing}....
• BUG [from telephone terminology, "bugs in a telephone cable", blamed for noisy lines.
  ] n. An unwanted and unintended (and undesirable) property of a program. See FEATURE....
• green lightning: [IBM] n. 1. Apparently random flashing streaks on the face of 3278-9 terminals while a new symbol set is being downloaded.
  This hardware bug was left deliberately unfixed, as some genius within IBM suggested it would let the user know that `something is happening'....
• heisenbug: /hi:'zen-buhg/ [from Heisenberg's Uncertainty Principle in quantum physics] n.
  A bug that disappears or alters its behavior when one attempts to probe or isolate it....
• bug n. An unwanted and unintended property of a program or piece of hardware, esp.
  one that causes it to malfunction. Antonym of feature....
• wart: n. A small, {crock}y {feature} that sticks out of an otherwise {clean} design.
  Something conspicuous for localized ugliness, especially a special-case exception to a general rule....