What is Lemming Effect?
To get in an unnecessary line because you think you are supposed to. Most often at the entrances to concerts or other events, when there are several lines and it is difficult to discern which one is needed.
Person: "I stood in line for tickets for an hour, only to find out that I was in the line for people that already had tickets. I had to get in the ticket line, then go to the back of the line I was just in. The lemming effect strikes again."