She didn't want to buy from you. Maybe it took her an hour to figure it out. So what. That's her choice as the customer. If you didn't want to spend an hour with her than you shouldn't have done it in the first place. Maybe you were pissed off because the sale was more important to you than the person. I am absolutely sure that she knew this, and that is why she moved on. Good for her. She didn't want to hurt your feelings, but you were being a total jackass. She did the right thing to move on. You might have made a lifelong customer from her, if you had really cared about her, what was best for her, and what she wanted. Not what you wanted. She won't be back and either will her friends.
You missed another big chance here, because you put your fragile ego and a sale in front of another live breathing human being. Just reading your post of how you treated these people pisses me off.
You should have locked the door again when you went out to the car. The store was open, so the fellow was fine in walking inside and approaching you. That is why you are in business, isn't it??? Don't be a jerk. Treat people with respect. You lost three big chances to make long time customers from these people, as well as their friends. You did not need to spend 45 minutes talking with him, but you could have bent way over backwards being apologetic about having to leave right away, as you very gently kept walking to the door and asking if you could get back to him or help him the next day asap. Also I agree that you should have identified yourself as the store owner and that you would be delighted to help them.
Of course, because you destroyed that guy's business. Whoops, that guy was you. There's a clue for you huh.
The way you acted with those three people would definitely get you fired.
A great fellow who was a mentor to me, and who passed less than two years after we met, told me of how he would approach fsbo's, people selling their own homes, every sunday afternoon and evening. I said did people ever give you a hard time? He said oh yes one fellow pulled a gun on him. I pressed for details, and he said the guy hated real estate agents, grabbed a rifle or shotgun, I don't recall exactly what he said, and ordered him off his property.
I said, what did you do? He said, well I left! We both laughed, then he looked right at me and said, "but I went back the next week!" I said, you did? He said, oh yes, and he ended up helping that guy buy and sell quite a few properties through the years. I said, well you've got more guts than me because I would have stayed away from that place. But he gave me a great lesson in determination that I always remember, as well as remembering him, as he was a great fellow and everyone loved him. I don't go to funerals but I went to his. There were people there from everywhere, no one was talking and all were in tears.