In a regular programming language (i.e: Javascript), you may need try.. catch block in order to :

- Handle Errors

- Increase the fir

try {
   doSomething("...")
} catch(error) {
   doTheOtherThing("....")
}

Ansible has something similar which is block... rescue

This is an example : 

 - name: Handle the error
   block:
     - debug:
         msg: 'I execute normally'
     - name: i force a failure
       command: /bin/false
     - debug:
         msg: 'I never execute, due to the above task failing, :-('
   rescue:
     - debug:
         msg: 'I caught an error, can do stuff here to fix it, :-)'

Where : 

- block is an array of tasks

- rescue is an array of tasks as well

- block & rescue are attributes under the big task  "Handle the error"