There is a case where having N+1 queries are beneficial.
In Rails terms, it's when you perform Russian doll caching, but you can do this in any framework. The idea is you can cache a specific X thing which might make a query to an associated Y thing. A textbook N+1 query case (ie. a list of posts (X) that get the author's name (Y)).
If you render the view without any cache with 10 things then you'd perform 20 queries but after the cache is warm you'd perform 0 queries. If item 5's Y gets updated then you only need to bust the cache for item 5 and query only item 5's Y association. Performing a preloaded query to get all X 10 things with their Y associated things could be an expensive query.
You'd ideally want to do something like dataloader, where you look up your N Xs in a single cache query, and then do a single database lookup for the (N-C) Xs that weren't in cache. You can then either eagerly load the Ys with the Xs like you said, or do a secondary cache lookup for every Y, and potentially another single database query for the Ys not in cache.
Unfortunately this pattern gets really hairy if you're not using promises and an event loop.
If I had to move to another language, I'd really want to find a "powered by the event loop / dataloader" framework, i.e. Vert.x for Java.
Also, per dataloader, a shameless plug for our ORM that has dataloader de-N+1-ing built natively into all object graph traversals: