Some fires take little coaxing. You put the kindling together with the logs, strike a match, and shortly afterward the flames are roaring. Other fires require a lot of work. The wood may be green, wet or resistant and efforts that would produce success with other ingredients go nowhere.
So too is the case with teams. A leader has to make a quick assessment of the components and whether the result will be worth the effort. Some people are the equivalent of wet wood.
Beware of them.