Description:
DO

create user 'fooly'@'localhost' identified by 'sample';
drop user if exists 'fooly'@'localhost';  -- error 1064: you have blahblab
drop user 'fooly'@'localhost'; -- 0 rows affected

How to repeat:
create user 'fooly'@'localhost' identified by 'sample';
drop user if exists 'fooly'@'localhost';  -- error 1064: you have blahblah
drop user 'fooly'@'localhost'; -- 0 rows affected
create user if not exists 'fooly'@'localhost' identified by 'sample'; -- -- error 1064: you have blahblah

Suggested fix:
1) *if exists*/*if not exist* should be supported in DROP/CREATE USER
2) as one row was deleted from the `users` table *1 rows affected* should be returned

Thank you for the reasonable feature request.

Peter,
could you please report a separate bug for wrong row count?
Wrong row count is not a feature request.

created! http://bugs.mysql.com/bug.php?id=39762

Duplicate of Bug#19166, which is a duplicate of Bug#15287, etc.