misfeature: /mis-fee'chr/ or /mis'fee`chr/ n. A feature that eventually causes lossage,

:misfeature: /mis-fee'chr/ or /mis'fee`chr/ n. A feature that
eventually causes lossage, possibly because it is not adequate for
a new situation that has evolved. Since it results from a
deliberate and properly implemented feature, a misfeature is not a
bug. Nor is it a simple unforeseen side effect; the term implies
that the feature in question was carefully planned, but its
long-term consequences were not accurately or adequately predicted
(which is quite different from not having thought ahead at all). A
misfeature can be a particularly stubborn problem to resolve,
because fixing it usually involves a substantial philosophical
change to the structure of the system involved.

Many misfeatures (especially in user-interface design) arise
because the designers/implementors mistake their personal tastes
for laws of nature. Often a former feature becomes a misfeature
because trade-offs were made whose parameters subsequently change
(possibly only in the judgment of the implementors). "Well, yeah,
it is kind of a misfeature that file names are limited to six
characters, but the original implementors wanted to save directory
space and we're stuck with it for now."
-- The AI Hackers Dictionary