The reason officers pull in behind you and drive for a while with no overheads on is so they can do what's typically called a "rolling 10-28" which is a license and registration check through NCIC prior to stopping you. This lets them know right up front what they're dealing with. Sometimes, during certain times of the day and/or night, NCIC is updated with new information so it can be unavailable to officers on stops. Also, they may be waiting for a good, safe location for you and them to pull you over. Every place on the road is not safe and a few officers a year are killed by traffic hitting them while they're on a traffic stop. So see, they are not simply being jackasses and pissing you off. Would you simply walk up on a car you pulled over not knowing who was in there and what they've done in the past? Especially at night? I think not.
Here's Rogue's recommendations for dealing with officers on a traffic stop. First, keep your hands visible, preferably on the wheel or even on the outside of the door. Second, if it's dark out, turn on your dome light for them so they can see into your car better. This may negate them having to put their full compliment of lighting on you. Third, if they do put all their spot lights on you, it's to assist in obscuring your view of them as they approach their car, etc. Makes it hard for you to get a bead on them and get a clean shot off at them. Fourth, be polite and be calm and don't make any quick movements. Ask before opening glove boxes, reaching under seats, etc as these can be very dangerous places as far as a cop is concerned. Fifth, DO NOT give an excuse or even admit to the offense you "think" you've been pulled over for unless specifically asked. Even then, simply state the most obvious possible offense you "may" have committed and leave it at that. Giving a cop too much information amounts to additional guilt and/or possible other offenses that you committed, leaving them to wonder if this was an isolated incident. Finally and most importantly, just be polite and courteous.