Most folks have had the unfortunate experience of waiting in line behind a Karen customer, but believe it or not, it could be worse. Just ask this dude, who ended up waiting in line behind three Karens. This thread was posted to Reddit's r/pettyrevenge subreddit by u/jarjarmullet , who silently watched as this trio of entitled older ladies kept giving modification upon modification to their order. This, of course, frustrated the sole employee making sandwiches as well as the long line of custom…