A few notes to some of the sorts of customers I end up having to deal with:
Please refrain from drawing your weapon in a crowded store. No, I don't care that you're offering me ample warning. If you want to see if it'll fit a holster, please bring it in unloaded and check it at the door.
If you don't know what gun you're looking for, vague generalities will not lead me to find it. Yeah, maybe some magazine ran some story on it awhile back, but I don't know what the hell you're talking about. Especially if you call a gun that's been out for several years new, don't know the brand, and aren't sure of the caliber.
Likewise, please don't get annoyed when I don't know exactly which gun you want to see if you ask to see that youth gun (we have them all in one section), that black one, that Glock (there are quite a few), that .45 (again, one section), or that left-handed gun (once more, one section). I'll try to grab the one you are vaguely gesturing toward, but it's not always easy.
If you ask me which gun I'd pick, keep in mind that I am not you. I do not have the same hand size, budget, taste, or needs as you. When I give my opinion, I do not mean that it is better for you, just that it would be my choice.
Don't use me as your only research tool. Yes, I'm am often aware of which models are available in which calibers, but the best choice is the manufacturer. They generally know what they make.
If I am not entirely familiar with gun A, don't get mad at me. I'm certain I could find a few guns you aren't familiar with. Let me do a little research and I can tell you more about gun A. But you probably don't want me to know as much as you.
If you have been patiently (or not) waiting your turn with a number, you WILL be helped in numerical order. Do not ask me to help you because I'm near you or "it'll be real quick." That guy with the number before yours wants help just as badly, and he grabbed his number first.
If you aren't happy with a price, don't buy it. Yeah, I know we match prices and I know you think that the used gun should be cheaper, but don't come in and just complain about the prices. I don't care. I didn't price them. I'm not going to give you a deal. That used gun may be nearly as expensive as a new one, but it's in like new condition, so what do you expect? And the guy who sold it to us wanted a decent deal, too.
Finally, I don't like being treated like "the help" or your best friend. I am doing my job, you are hoping to buy something and get good advice. Let's keep this businesslike.