Use this phrase when you want someone to think differently about something that happened to them. You usually say this to someone who is thinking negatively about something. You tell them to "think about it as" something positive instead. For example, if someone breaks up with your friend, you can say:

Think of it as a chance to meet other people.

In the example at top, "Think of this as an opportunity" means that the listener should try to believe that getting laid off from his job will allow him to find a better job instead.