After the booking has been completed passengers will be able to rate their experience, by giving the booking a thumbs up or a thumbs down.
When a passenger gives you a thumbs up you will be added to the passengers favourite driver list. This will give you priority access to accepting all of their advanced bookings. Also your account will be given a positive rating. The more thumbs up (positive ratings) you receive you will be given priority access to accepting higher value bookings in which the passenger does not have any favourite drivers.
If a passenger gives you a thumbs down for a trip you will no longer be able to view job offers from that passenger. Also your account will receive a negative rating, impacting the amount of bookings that you are offered.
What this means is you should always be providing the best possible experience for all passengers that book through the app.