misfeature /mis-fee'chr/ or /mis'fee`chr/ n.
[common] 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."