If you filter a view by a 'many to one' field, like for example any term reference field, and dare to filter by multiple values ANDed together, then the views query produced can have many, many, many joins.
MySQL can choke on this, badly. A small production site with a small set of tables produced DB queries that took over 3 days to execute!
Instead, we change the query added from being lots and lots of joins, to instead a single subquery condition.
This will work for small datasets and probably not for larger ones.