Appearance and attitude....starting with what someone is driving, can make a big difference in how you are treated.
Example, I was running 80+ one time on US1, right along with and just behind another truck. State trooper runs up on us in the inside lane, slows behind for a minute (getting/running my plate, I'm sure), then goes and immediately lights up the truck in front of me. Difference in the two trucks?? The other guy had a big "No Fear" decal across his rear window. 90% chance the trooper was looking for additional violations, and/or an attitude problem, so he could flex his ego a little. He picked the vehicle most likely to garner that. (And I rolled on, pegged on 65).
I've been carrying concealed since before the NC CC law. Probably had 20 or so interactions with the police while carrying. All but one of those were things like license checkpoints, etc (the other was expired tags in a borrowed Lincoln--and that was at midnight in Greensboro). I've NEVER had a problem...never had a pistol taken from my possession, or serial numbers run, or asked to search my truck. At the last DUI checkpoint I went thru, the state trooper's response when I presented my ID and told him I was carrying was "Good, that's the way it ought to be" and he waved me on.
Lucky? Appear innocent enough?
Biggest run-in I've ever had was down at Sunset Beach at the Food Lion a couple of years ago. I parked in the fire lane while my wife ran in. I stayed in the drivers seat and kept it in 'drive'. Less than a minute later, two cop cars blocked me in front and rear....it took three cops to come to my truck and tell me not to park there.

I ID'd, told him I was carrying (x3, pocket carry, center console, and in a bag on the hump). I was expecting at that point to get dragged out face down (their entertainment for the day), but at about that point, they just said to move and park it out in the lot...about then my wife came out, and we drive on.