I had the same feeling the first time I used the J lounge in C in DXB. It is too big and impersonal and with what felt like walls along the entire length on the edge purposefully making it impossible to look out at the aircraft. You might as well be in a warehouse or under the ground. But then again how else do you connect every gate directly to the top deck of an A380? By its very nature that means a lounge exactly as long as the concourse you're in, which is nearly 950 meters. So you will have lots of empty open spaces making the place feel as dead as a morgue. At the far ends you can look down into the F lounge below and it looked as dead as the J lounge - but then very few people would venture that far unless their gates are at the end.

The B Concourse J lounge of course is from a time before they wanted direct access to the top deck and you have to go down to get on your aircraft. It is still a very long and impersonal lounge in my book.

The DBX J lounges are strange places. Two hours max in there (as suggested above) is about right in my book.