Sign of the times?
We used to have gunshops all over the country. Today we have some gunstores, and stores that sell guns. Plus we have the Internet, and a changing demographic for the market. There are a few of the old time shops left, but nowhere near what there used to be, and they are fewer and fewer all the time.
Part of the reason is the change in our culture. And its not just guns, its time. When I was a young man, the old boy who ran the local gunshop was nearly always there, and even though he was decades beyond retirement age, he always had time to talk to you, invite you for coffee, see what it was you wanted, and do whatever he could to help you out. He was such a great guy, it was almost embarrassing to pay him.
On the other hand, his regular clientelle wasn't 300 guys who came in to fondle and leave fingerprints on the stock, and then buy online or at a chain store because that would save them $8!
I've been in and around gunshops and stores for over 40 years, and these days, its the worst its ever been. In between clerks who are doing you a lifetime favor just looking in your direction and customers who want diamond studded gold for the price of a cup of coffee (and get offended when they don't get it), its not as much fun as it used to be.
Many places have a "captive market", and get rude because they know it. Others get rude because even though you're a good guy, and would be a good customer, the last 298 guys through the door were jerks. Its tough to maintain a good friendly attitude when guys bitch about everything you don't have, waste 20 minutes of your time looking at stuff, and then tell you that they are getting it at Walmart because its $20 cheaper there!
Certainly, you have the right to vote with your wallet, and go where you want to shop. But a little kindness goes a long way, on both sides of the counter. One thing I will tell you, just packing in and going elsewhere because you got snubbed some way doesn't fix the problem. In the long run, it may close the business, but it doesn't FIX the problem. Making sure the owners know why they lost a sale, that goes a long way to fixing the problem.
I've done this before, with other businesses, as well. Don't just leave when they are rude, make sure the people who's bottom line is affected by the loss of business know exactly WHY they are losing your business. You'd be surprised at how much change can be made when the boss finds out his counterman's bad attitude is costing him hundreds in lost business, most likely every day!
On the other side of the coin, everybody has bad days, and sometimes, even through they should try to be nice, they slip. I've done it, you probably have too. I can overlook that. But, if your job is to be nice, you really should work at it, especially on the bad days.