In such a situation, the appropriate response can vary depending on the context, but here are some general guidelines:
Stay Calm: Even though it might be frustrating, try to keep your cool. It's important to approach the situation with a level head.
Politely Point it Out: If you feel comfortable doing so, you can respectfully point out the situation to the person. Say something like, "Excuse me, I think there's been a misunderstanding, but the end of the line is actually back there."
Involve Store Personnel: If the person refuses to acknowledge their mistake, or if you feel uncomfortable addressing the situation directly, you can speak to a store employee or manager. They are typically trained to handle these types of situations and can help resolve the issue.
Ignore It: If the line is short, or if addressing the issue seems like it might lead to conflict, sometimes the best option might be to let it go. It's important to choose your battles wisely and remember that sometimes it's not worth causing a scene over.
Keep Things in Perspective: It's easy to let little things like this ruin your day, but it's important to remember that there are many more important things in life.
It's also important to note that sometimes people may accidentally cut in line because they didn't realize there was a line or they didn't see it. Also, there might be cultural differences at play; in some cultures, lining up is done differently than in others. It's important to give people the benefit of the doubt.