Sometimes, we feel we need to keep distance from what we say. Maybe because we intend to say it as gossip, or perhaps we're not sure of the veracity of the facts. It may also be because we don't want to be given the authorship of the ideas we express.
For that reason, we have the expressions of distancing, which allow us all the possibilities above. As always, this is a matter of practice, so make sure you revise the activities included on the slides, corresponding to the exercises on the Grammar Bank on your Student's Books.