I fly a lot. I typically do close to 100,000 miles in a year.
Anyone that frequently flies goes into what I call Airport Mode. This mode essentially means you zone out other people. You ignore crying babies. You are indifferent to people that talk loudly. You tolerate idiots that cannot squeeze their tuba-sized suitcase into the overhead bins.
The hardest thing to ignore is a bruised shoulder. This happens when an inconsiderate person insists on wearing their book bag on the plane and then smashes it against your shoulder while they are walking down the aisle.
Your book bag doesn’t make you rude when you are walking in a straight line. However, when you turn it is quite likely that you don’t realize that you are now quite deep.