I've had those things happen to me, too. I TRY to remember to take a deep breath and ask myself, "In 20 years is this going to matter?" But I am human, and not perfect, so of course I do lose my temper at times, silently. But it is so annoying, and many times I have just been a knot of stress when I get to my car. The most usual one for me is that main aise in Walmart going from the front to the back of the store. Almost every time I'm in there, no matter what day or time, there is usually a "family reunion" taking up the whole aisle. So I have to move my cart through the clothing section to get past them, so I can go pick up a gallon of milk.
Another thing I have noticed since moving here, that I have never seen in any other area of the country is the cluster at the entrance of every store or building. No matter if you're going to the bank, grocery store, post office, or mall, there is always a cluster of people gathered at the entrance, neither going in or coming out... but they all gather right in the entry and often, the doors are permanently open as the "cluster" won't move to let people in or out of the building. Very strange, and I have never seen that anywhere else. I've seen crowded entries where a lot of people are coming and going.... but these are large groups of people gathered in the entrance visiting and chatting, not trying to enter or leave.
And some people wonder why I hate to shop and rarely leave my house. I'm afraid of being sucked into "The Cluster" and not being able to get back out..... LOL!