Social capital can be very easily destroyed. It can take a long time to build social capital through repeat positive actions and interactions, but it can be destroyed by a single action.
Generally social capital is lost or damaged by anything that reduces feelings of goodwill or disrupts networks. Any action that is antisocial. Anything that makes people feel less social, sharing, giving, or caring towards their fellow humans. These actions could be things like a betrayal of trust, selfish acts, perceived indifference or exclusion, violence or threat of violence, or deceit or deception.
Social capital can be destroyed much more easily and rapidly than it can be created. One serious misjudgement can undermine long periods of trust-building, destroying an individual or even a community’s reputation.
Often the effect on social capital is the result of how an action is interpreted. An action may be well meaning but could be interpreted as negative. All actions and events are signals that affect social capital. For example, when someone commits a crime we could say there is a reduction in general trust in society, but if that person gets away with it then there is loss of trust in the systems of society that create order and predictable behaviour.