Reminds of of the time I queued at Aberdeen at a BMI desk, for 55 mins, and I was next in line! One large family holdng up the queue and the agents didn't even open another desk up? When asked how much longer we'd have to wait as the flight was due to board, a surly b*tch gave us the glare and replied with "As long as it takes".
I agree that a lot of people use their position as an outlet of frustration. Threats of not boarding you etc. are all part of the little man/woman scenario. It's been getting worse for about fiftenn years IMO.