Always, always, always “manage up”. When people in some service role like a counter person for an airline hold this much power over you, you lose almost nothing by treating them like they are the most important person in the universe. Talk them up, be overly kind, do everything you can to make their job and life easier. It isn’t fair, but I have found you will experience much less friction in life following this philosophy. Are they right? Is Anthony from the linked article “right”. No, of course not, but they have a sliver of power that happens to be extremely important to you for whatever reason and they can and will hit you with it as hard as they can and you never know what someone else is going through or where they are at in life. Don’t chance it, at least not over small stuff like this.