10. The Machines (Mostly) Don't Blink
On the movie's home video commentary, Cameorn mentions that he wanted the Terminators to blink as little as possible, in order to suggest their inhuman nature.
While there are a few instances throughout the film where both the T-800 and T-1000 do indeed blink, they're pretty infrequent and usually reserved for when the two are firing weapons.
In fact, Robert Patrick even underwent weapons training specifically to avoid blinking while shooting, and bar the odd blip, he certainly pulled it off.
While you can argue that cyborgs designed to infiltrate humanity should probably have been programmed to blink, it is a neat little detail nevertheless.