In a word, yes, I have encountered irrational impatience at an interection. My own version of the situation escalated and got bizarre pretty quick...

Last Spring I was commuting to a college campus on my bike. I was in a similar situation, approaching a small but busy intersection with a stoplight instead of a stopsign. I had no traffic in front of me and a single dingy black SUV about half a block behind me. I have had problems in the past being harassed by undergraduate drivers around the dorms, so around 30 feet from the white stop line at the intersection I pulled to the gutter of the parking lane to let him pass in front of me to avoid his potential impatience.

After he pulled all the way to the white stop line I rode back into the lane behind him and to the right. My front wheel was two or three feet behind his rear bumper. There were no cars behind me, so it was just him in front of me, waiting at the light. When the light turned green he stayed stopped and I figured he must be on his phone... and he kept waiting. I could have dashed around him, but that would have been dangerous if he decided to turn without signaling, which is so common these days. All of a sudden he rolls all his windows down and starts screaming torrents of profanity and threats at me. In between the swearing and threats he tells ME to go first! I was astounded!! I yelled back to him "You're at the light! You're first in line! You go first!" That only made him go even more totally insane and start waving his fist at me through the sunroof. At this point students walking around near us have stopped to stare and we have the attention of the stopped cars at the cross street. He flatly refused to move and in the midst of his abuse he insisted that I go AROUND him through the intersection.

This was my third or fourth angry encounter in the area. Every other time an angry driver went insane because he thought I was slowing him down even though I was riding 22-23mph in a 20mph zone. I never in a MILLION YEARS thought someone would go nuts because they WANTED ME IN FRONT OF THEM.

I was confused and upset, but I had an appointment with my graduate advisor to keep and the light was about to change again, so I unthinkingly did as the jerk demanded and rode all the way around his car to cross the intersection, yelling back that he was a total moron. In retrospect this was incredibly stupid because he could easily have run me down in a fit of roadrage. You really never know with these nuts. After my meeting I emailed the dean of the grad school about my incident and later in the week there was a campus wide email about the rules of the road with bikes/cars.