Filter users in views with a mandatory role and another role that is optional Suppose I have a Role A and Role B. 
As per my requirement The Role A is mandatory for a user and the Role B is a good to have role.
I want to filter out the users in the views. So If a user has only Role A, he should be listed. If the user has both the roles he too should be listed but if the user has Role B only he should be restricted.
Please Suggest.
You can put condition in View's criteria. 


Go to your view and step ahead to filter. 
Put first filter as. For example you have role as category A and category B.


Add following filters which can be helpful as per your scenario.

   Select content:role (condition : is one of A and B)
                    OR  
   Select content:role (condition : is one of A)
                    AND  
   Select content:role (condition : is none of B)



Don't forget to add OR and AND condition in between filter fileds.


Hope this will be helpful.