Standing in a long line is one of the last places nobody expects anything from you. Enjoy it.

A queue is enforced nothing. You cannot work, you cannot leave, nobody can hand you a task, and the whole situation is outside your control, which sounds like a problem and is actually a rare condition. Almost every other gap in a day comes with an implied obligation to fill it usefully, and this one does not.

Try one line this week without reaching for your phone. Look at the building, the people, the strange things on the shelves near the till. Let yourself be bored on purpose. It is seven minutes with no demands on it, and there are not many of those left in a week.