It's incredibly frustrating when you only need ONE item from the first boss of an instance and you then get locked out for HALF AN HOUR if you don't want to clear the rest since you don't need anything at all from the rest of the place and you're just wasting time.
Not to mention LFR is nearly the same, I queued for 2nd half of MSV the other day, got put in at elegon, so I cleared the rest of it and requeued.. only to be put back into elegon. This happened 2 more times.
Not to mention i'd get deserter if I left, and I couldn't spam requeue for a fresh run because some genius decided they'd stop telling you how many bosses have been killed already.
That has got to be one of the most annoying changes they have ever made, wow.