The problem with the video is, we don't see her actually enter the store - so we don't know why she was acting the way she did. Either way, looked like she thought she was entitled to her Pizza first. "Victim" was on the phone, and made a comment to whomever he was talking to about her beligerant activity. (there IS volume with the clip if you turn it way up. He said something that pissed her off)
On the other video clip out there, it shows it from the VERY beginning. The guy on the phone was on what appeared to be last in line. He was chatting with his GF when the GM walked in and proceeded to cut in front of him. He mentions that "Looks like it will take longer now that someone has just cut in front of me..." (Or something to that effect) That's when she flies off the handle and gets rowdy. All because he had the "cojones" to make a remark about her actions. Like HE did something wrong?!? How dare he make a smart remark to her heiness?? Geeesh!