Cooperation cannot be forced and group members cannot escape from each other, so
there is a common and natural tendency to avoid conflict or issues which might activate conflict. A focus on what everybody agrees about gets nowhere.
Achievement is the property of the group as a whole, so
it can be difficult to avoid free-riders who get credit (or claim it) despite having done little.
Consensus, even in the most productive groups, can be
time-consuming and you may miss opportunities or have to settle for mediocre, lowest-common-denominator results.
Win-win in distributing work and rewards may
produce dissatisfaction, because no-one ever feels they get enough, or that their efforts are appreciated enough. You may end up with a stalemate.
Being of service and providing individual attention
to group members has the potential to drain energy and diffuse effort, while often making people more unhappy.
Accepting people as they are can be
an exercise in frustration and you end up desperate for a better bunch.
Maintaining morale can be
draining and time-consuming.