To act or not to Act

If someone sees a crime being done and doesnt do anything this is a crime in in itself. If you see someone being bullied and you dont step in or say anything then youve done wrong. If I saw someone steal some sneakers from a store I would definetly not get involved. It all depends on the situation and its a very difficult question. The person who doesnt act though did do wrong but should we punish them, I dont know.