Feature creep

Feature creep (or creeping featurism) is the systematic tendency to load more features onto systems (often for aesthetics or convenience) at the expense of whatever elegance they may have possessed when originally designed. For example: "The main problem with BSD Unix has always been creeping featurism."

Description
Feature creep is generally described as the tendency for anything to become more complicated because participants keep insisting, "Gee, it would be even better if it had this feature too." The result is usually a patchwork because it grew one ad-hoc step at a time, rather than being planned. Planning is a lot of work, but it's easy to add just one extra little feature to help someone, and then another, and another... When feature creep gets out of hand, it's like a cancer.

Usually this term is used to describe computer software, but it could also be said of the federal government, the form, and new cars. A similar phenomenon is known to afflict conscious redesigns of existing products.