The "what if?" mantra is anti-design mentality. That occurs when you're either to inexperienced with a piece of functionality or just to lazy to design it correctly, thus giving a part of your code more data than it needs. Some symptoms are:
Your class has so many functions it looks like Java: your class has every possible function you could think of, "just in case you need it".
Your function looks like Win32 API: your function has one parameter for every variable you can pass it, "maybe some could be used for something".
You're using the F'in Singleton Pattern or F'in Globals (same principal): by making everything singletons/globals you're infecting every piece of your code and all that it touches with symptom nr 2 since now everything can get ahold of all possible data variables you've created.
