Nobody's mentioned attitude so I'll add 2 cents. Dot guys are not dummies; they're there to do a job, often a ####ty one--figure just how many drivers they see in a day. They seem to tell within 15 seconds or so if you take pride in your truck, or are trying to hide something or are combative. Give them half a chance to be nice and they probably will be, but if they get 'attitude' they're going to show you that their's is definitely more powerful.
And have your paperwork all nicely organised; a 3-ring binder with licenses, special permits, inspection documents, repair logs--when you produce something like that with everything neatly filed and tabbed you'll be amazed at the response you get! Rustle around a bunch of junk in the glove box or off the dash or floor and you can bet they'll look for more wrong.
I haul over 500 loads a year of 110,000 lbs on 6 axles, logs or lo-bed, and get pulled in to routine checks periodically and go over scales a lot; I just never have any worry going in and have yet to have a bad experience. I know they do happen, but wonder what display of attitude set it up to happen that way.
I dunno, maybe I just look to old to hassle?