We absorb the emotions of those around us which in turn affect our own feelings and behaviours. Some of us are more susceptible then others, but we all suffer from this process, much as we may find it an abhorrent assault to our rationality.
To find reason cast aside on a wave of emotion and diluted, lost in a sea of contemporary outrage.
For examples of this phenomenon, note how even one persons bad mood can bring a room down. How stress can infect and spread, go to london at rush hour and try not to hurry or threat, to not shop in hong kong or in town in the run up to christmas.
Note this is more than mere empathetic understanding, it is a force, an invasion permeating our barriers and overriding our individual emotions.
Look at the behavior of crowds, the atrocities perpetuated by otherwise ordinary peoples. Emotional osmosis is a social force. We must recognise these forces at play within our collective mindset if we are to ensure that the future path of humanity is governed by reason and not swept along by emotional tides.