Adding last-minute features, whether in response to competitive pressure, as a developer's pet feature, or on the whim of management, causes more bugs in software than almost anything else.
Of all modern notions, the worst is this: that domesticity is dull. Inside the home, they say, is dead decorum and routine; outside is adventure and variety. But the truth is that the home is the only place of liberty, the only spot on earth where a man can alter arrangements suddenly, make an experiment or indulge in a whim. The home is not the one tame place in a world of adventure; it is the one wild place in a world of rules and set tasks.