There are conspicuous signs around this location that emphasize that tipping employees is forbidden. Try to resist the urge. (/sarcasm)
Get here early. Even if you do, the wait will likely be painfully long. Employees are about as friendly as one would expect, but they are far from helpful. I had a more challenging situation when I last went (car leased out-of-state being registered for the first time in NC), and I had to come back on three different occasions in order to properly register my car because of the lack of information provided. I guess I was destined to suffer a bit longer in my own little circle of Hell.
It's my understanding that this place is no longer staffed by state employees, so why aren't there better hours? I hate having to take a sick day to suffer in this pit.