Today in a boutique the SA said something rude to me.

This has never happened to me before, and I am wondering if, in my decades of shopping, I have developed an insensitive attitude when boutique shopping. I know quite a few of you have retail work experience, and I would appreciate your opinion on appropriate shopper behaviour.
I enjoy shopping so I am usually in a happy mood in store. I often exchange
pleasantries about fashion with SAs at the checkout. Even when I don’t buy anything, I make a point of thanking the staff for all their help. But perhaps I have developed into an annoying shopper without ever knowing it. Perhaps other SAs in the past would have liked to say something similar to me, but didn’t dare.

The story:

Whenever I’ve dropped in over the years, the boutique in question has always been staffed by the owner and her SA;both women are of retirement age. I have never found them as "warm" as most retail staff you meet, but I do think I have always been friendly and courteous to them. The stock
veers to the plus-sized (I am not plus sized) so there is not a lot of choice for me-- I have only bought about 2 or 3 things over say 5 years--but I am always attracted by the stock, which has a lot of flair, and I am always hopeful.The shop is near my hairdresser who is some distance away from my home,so I only ever go there after my hair appointment. I always “style up” when I get my hair done, so I like to think that I present as fairly fashion-conscious whenever I have been to this shop. I know I won’t get another chance to go back there till next haircut, so I always have a pretty thorough look through the racks, and usually pick out quite a few things to try on.

Last time I was there I found about 10 things to try. The shop has 2 change rooms, but on the last few occasions, one of them has been unusable because of stock in plastic bags hanging on the changeroom curtain rail. Usually there is no other customer in the shop. While I was changeing , I heard the SA saying to a customer that the changeroom was occupied and that she would have to wait. The customer was gone when I emerged, so evidently she decided to leave instead. I had the impression that the SA
was miffed that I did not buy anything after “causing” a potential paying
customer to leave.

This time (2months later) when I walked in and started picking out garments
from the racks, the shop owner said to me “ 3 garments only, thank you”. I
guess she (or the SA) remembered what had happened last time. I said “of
course, no problem” and complied. I only wanted to try 3 items, as it turned out.While I was in the changeroom the SA said (from outside) that I could hang the unwanted items on the changeroom curtain rail (there was nowhere else to put them anyway) and I said “certainly”.

I looked at my watch,saw I was getting short of time to get to my next
appointment, so I hurriedly put the first unwanted top on its hanger and slipped it onto the end of the curtain rail. The long sleeves were not pulled through properly, but I figured I didn’t have time to do that. The SA took it, and then I heard her say from the other side of the curtain, loudly enough for anyone in the shop to hear, “Couldn’t even be bothered to hang it up properly!”

I was ready to march out in high dudgeon –-but I wanted to buy
the third top, so I swallowed my pride, wrangled the second unwanted top that kept slipping off, back onto its hanger, and went calmly to the register. I had to pass the SA, so I apologised to her, saying “Sorry I struggled to put that top on the hanger; I’m actually in a bit of a hurry.” She did not reply. I paid the owner in a polite professional manner (no chit-chat this time) and left. I won’t be going back.

What is the proper and mostrespectful way to go about trying on garments in a boutique? Should I always hang each garment back properly on its hanger? Am I also supposed to put it back on the rack it came from? Have I become lazy through too much chain store shopping, where
the SA’s take your unwanted, unhung garments with a smile, saying “Don’t worry about that, I’ll fix it”? Those of you with boutique
experience, what does a “good customer” do ? what should I avoid doing in the future? I don’t want to offend retail staff, so all suggestions are welcome.