If I'm in a mood that day I might say something but somethings in life are best left alone, a confrontation with them could ruin your evening, just think to yourself I'm still going to make it on that ride or whatever it is you were waiting for

She needed to be told that she was being rude and unfair to the next person. But I politely always say something because I'm not totally invisible and I'm never rude but always tactful and respectful. And besides that...I was there first. On occasion I may allow someone to go ahead if they only have 2 items and I have a cart full. I'm not a mean or disrespectful person. But fair is fair. I have had a time when a older person jumped in front of me. I let it go..until I learned that she did this all the time. Then I politely told her I was sorry she meant to step to the back of me and not the front...that I was clearly in line holding 1 yes 1 item...She cursed me (I snickered) she cursed that too.( this time I was quiet because at that point it was no longer funny or cute) The attending officer caught it because she saw the whole thing. She saw her do this all the time and it was a habit with her. But the twister is she was a pick pocket. She had a reputation in the store for doing that( jumping the line) and it was not cute or funny. I was told different customers handled it differently. Bottom line please wait your turn and stop playing with peoples emotions. In this day and age someone could get hurt. I personally am not speaking of hurting a older( or anyone) person who just skipped the line with me standing there but who knows what the next person is thinking.

Of course i will make a scene , what if you been in a train that you have been Q-ing for 2 hours and suddenly out of nowhere another guy just bump in the Q , for he says he's late for work or another reason , i just can't take it , if it happen to me i will swing my fist to his face whether he like it or not

In this case I'd probably say nothing. The idea of a line is to get people served as quickly as possible, and like it or not, making a scene will just slow things down and make ME the one who's keeping people held up. People'd probably be more upset with me than they are with the person who cut in the first place! Now, I might give the line-cutter a dirty look or something, but that'd be the extent of it.

I do something in-between. I politely let the person who broke in front of me know that he erred. Most of the time people who cut just aren't paying attention and will apologize and move to the back when someone says something. There is no need to make a huge scene unless you like attention.