Crowdedness is a mood or drive your creatures feel at times when they have been spending too much time around other creatures. Some creatures attempt to fix this by walking away from other creatures, and some creatures attempt to fix this by expressing how crowded they are. Some creatures even learn to fix this by hitting other creatures, so that they'll go away. Some norns don't appear to be affected by crowdedness at all. Its opposite is loneliness, although in C1, loneliness does not cancel out crowdedness.