There are few people in this world you should not piss off, for one reason or another. You don't want to piss off your waiter, because they handle your food. You don't want to piss off your significant other, because then you won't get any. You don't want to piss off the 6-foot-5 guy in the bar, because eating through a straw sucks. Most of all, you don't want to piss off your engineer. Making a record costs a lot of money, and while you may think your music is amazing and anyone working with you should be reveling in the fact they're involved with the reincarnation of <insert your musical hero here>, that's just not the case. First of all, engineers are already weird people. They sit in front of a screen listening to the same music over and over again. Whether they liked the music to begin with is irrelevant, because by the end of the mixing stage, they hate that music. With that in mind, don't evoke the beast inside your engineer. They already have enough problems.
Prepare your spines for pain.