Enforcement./Commitment All projects adhere to certain rules of conduct. When these "rules" aren't being enforced, things go down the drain rapidly. This can range from CEOs that ask for last minute changes twice a week without going through the normal RFC process to coders that say "Lets do that unit test later" or "I'll document the stuff later". Once enforcement becomes lax, it quickly gets out of hand and creates a downward spiral. A big part of project management is accountability, once that gets eroded, it becomes very hard to get it back.
Sure there will be times when this is inevitable, but these should be the exception and not the norm, no one should think that its "ok" or "normal" to short cut the system or the team will be dysfunctional eventually.