Tamar, IMHO humans are as affected by entropy as the whole universe... we have a tendency toward chaos. ;-)
"Mob instinct" is a real entity. I've seen a peaceful concert turn into a riot in about 5 minutes with the city's finest youths mingling with habitual criminals to smash shops, overturn cars and create scenes that caused even the participants to rear back in dismay the following day.
Perhaps we have an equally powerful mob instinct in the opposite direection, towards love, community and sharing, but I've not seen it spontaneously.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1