Agree on struggling for real scenarios where you'd use a right-join, but your example with

select * from dogs where owner_id not in (select id from owners)

You wouldn't actually recommend something like this would you? The query plans for sub-selects vs. left-joins are very different, with lots of implementations having limits on the "in" clause.

Kind of funny that the way you'd feel if you saw a right join is similar to how I feel about sub-selects!