> Inexperienced devs, not taking enough time to understand problem, not spending enough time brainstorming the problem Requirements changing is also a big one.

> Inexperienced devs, not taking enough time to understand problem, not spending enough time brainstorming the problem Requirements changing is also a big one. 4 years into one project that I had created and maintained a "one to many" relationship changed to a "many to many" in some of the tables central to the system. Something that I had clarified wouldn't when originally designing the system.