Here's a pet peeve of mine: equipment (especially camera) designers and engineers who apparently have *never actually installed* the type equipment they're designing, and come up with some of the most bizarre concepts that make physical installationa headache.
A classic example, for me, is the Pelco ICS-111 outdoor vandal dome: the camera module sits within a springy bracket that then rides in a groove in the housing, to provide a "rotation" axis. I'm sure it seemed like a good idea at the time... but most of them I've installed, there's a slight looseness to the "springiness", and it doesn't sit evenly within the groove - four contact points, and usually only three of them actually make contact (imagine a four-legged table with one leg shorter). This makes it more likely for the entire assembly to get bumped out of place, or just shift under vibration.
Another is the venerable Panasonic gimbal design as used in the CW484/504 and similar dome models - the very need for a locking screw on the rotation ring shows poor underlying design; the spring-loaded tilt pivots fail to hold the camera module steady much of the time; and the "twist" to rotate the camera module within its holder is invariably tight and gives little to grip, making that adjustment difficult to turn without throwing something else out of whack. Meanwhile, at 1/3 the price or less, the CNB domes we use have the same style of 3-axis gimbal, but have no requirement of locking screws or springs, but with just the right amount of friction, are easy to adjust while never (so far) slipping out of place on their own.
Oh, and don't get me started on the ol' Pelco IS-90, where the service video port is a sub-mini TS jack (hard enough to come by a plug in the first place), buried deep within the housing (meaning your average DIY solder terminal sub-mini TS plug won't fit with its cover on, let alone allowing room to get one's fingers in there)... and Pelco never bothered to actually include an adapter cable to allow one to plug in an RCA or BNC service monitor, meaning you HAVE to go out and find your own plug and build your own cable if you actually want to use the thing. It's like adding the port was someone's after-thought on an A&E spec, with no concept that someone might actually want to use it.
I could go on and on... it invariably seems the bigger the brand name and the more expensive the camera, the less throught was actually given to INSTALLING it. The more installer-friendly cameras seem to consistently be the cheap, no-name models...
Okay, one more: certain Arecont domes that use hex-key locking screws for various adjustments... but actually DIFFERENT SIZE hex keys for each different adjustment. At least they're nice enough to include all the required keys, but seriously??? That's beside the multitude QA issues like hex-key screws that never actually had the hex stamped in them (just a little drilled hole)... parts mis-assembled and broken from the factory...