I understand. The comments were indirect. That is, people were queuing normally, quietly and orderly, each one with their smarthphone or taking care that the children did not get into mischief, etc. But when I started to read the book, people became mysteriously restless. It's as if someone in a traffic jam turns off the car engine, it's as if reading a book would indicate to them that the delay would be longer.
The thing is that when the cashier went to see why people were getting restless, she rebuked me, because I understand that it had already happened to her more than once.
And she would know from personal experience that every time there is a long line and people take out a book, the rest of the people get nervous.
I hope I have explained myself. Have a great weekend.