As The Washington Post has described, the use of untrained support animals as a psychological intervention is unsupported by the academic literature. But that hasn’t prevented the medicalization of pet practices: A letter from a doctor, available online for about $200, allows the bearer to launder a want (“I like having my dog with me”) into a need. (“My medical condition requires me to have my dog with me.”)

This letter magically changes who is doing the imposing, and allows you to become indignant when someone won’t let you take your untrained dog somewhere. You get to have your pet with you at your seat, and you also get the moral high ground…

But the pets-on-planes trend is part of a much larger trend: The proliferating sense that we are entitled to have the world adapt to our preferences, instead of the other way around.