@whitequark

I think this is an area where lack of shared knowledge can bite. If one thinks that others are not sad about the same state, one can for example assume others don't find it sad, think that they're different, and feel more lonely, or one can try to establish whether they actually think they're both true and bad, which usually makes others sad. (Obviously these are not the only two choices, and the outcomes do not necessarily follow from them -- esp. when one is more skilled at interacting with the kind of people one has around.)