I'm in agreement with ODB (and with the nameless scolded CO). I've witnessed countless good, bad, and ugly interactions between Soldiers and civilians. I can count on one hand the number that were the result of poor training or inadequate information. The rest were just the result of cocky 18-year-olds (redundant?) being jackasses. I almost never had to "re-train" anyone (nor direct an NCO to do so) because Soldiers already know how not to be belligerent. Most of it was simply discipline. My two nuggets of wisdom to my Soldiers (in highly sanitized formatting to keep it family friendly)...
1. Dealing with detainees: your job involves being shot at; their job involves shooting at you; if you don't like that, you chose the wrong line of work; if you're a little wuss who can't take getting shot at, fine, let us know and you can go to battalion; otherwise, don't be whiny little wuss and take out your frustrations/gynecological issues on detainees.
2. Dealing with locals: you think these people owe you gratitude or owe you cooperation? That's nice. Guess what? Nobody cares WTF you think. Now STFU and do your job, which includes being nice, gracious, polite, and making them think that becoming an American Soldier requires passing a congeniality test.

Total time required for this briefing: 30 seconds.