Military combat uniforms have two purposes: to camouflage soldiers, and to hold together in rugged conditions. It stands to reason that there's only one "best" pattern, and one best stitching and manufacture. It should follow that when such a uniform is developed, the entire military should transition to it.
In 2002, the Marine Corps adopted a digital camouflage pattern called MARPAT. Rigorous field-testing proved that it was more effective than the splotched woodland pattern in use at the time, and the Combat Utility Uniform (of which it was a part) was a striking change for such a conservative institution.
Not to be outdone, the Army drew up digital plans of its own, and in 2005 issued a redesigned combat uniform in a "universal camouflage pattern" (UCP). Three years after the Marines made the change, four years after the invasion of Afghanistan, and two years after the invasion of Iraq, you might think the Army would have been loaded with data on how best to camouflage soldiers in known combat zones. You would be wrong.
In fact, not only did the Army dismiss the requirements of the operating environments, but it also literally chose the poorest performing pattern of its field tests. The "universal" in UCP refers to jungle, desert, and urban environments. In designing a uniform for wear in every environment, it designed a uniform that was effective in none.