Having spent a fair amount of time in a lot of studios (mostly on the studio side as a player vs. the control room) I too have been surprised at how often the engineers fail to be nice and do indeed act like the musicians are a pain in the ass (although I suspect numerous encounters with self absorbed musicians may be the root cause of that). I am sometimes amused when the 2nd or 3rd engineer (perhaps someone who just last week was still cleaning the toilets) already have an attitude.
I make every effort to be cooperative, to delay any questions until the engineer is done with the set-up, to ask whatever questions I have in a way that takes the least amount of the engineers time and attention, and most of them still act rude. Oh well, having engineered enough crappy sessions myself, I guess I can understand how an attitude can develop.
A suppose that is why the producer has to work betwwen the artist and the engineer - (it's the producer's job to communicate and draw out the best performance, etc) the problems come in when the same guy acts as the producer and engineer and can't figure out which hat to wear when!!!