How could you possibly know where a grunt/scowl is directed when there are so many possible targets.

For me, only once. There was a long line waiting about 15 minutes for the ID checker to show up with me second. Then, finally, after the checker appears, the guy at the head of the line starts searching for his ID. Searching ... searching ... searching ... then the checker saved his life by pulling him aside as the angry crowd surged forward.

I always leave space for people to go around me when I'm loading all my stuff into the plastic buckets because I need extra time. Some go around. Some don't. I don't really pay attention.