The airport is the only place where people can be absurdly early and still feel like they are going to miss their flight. 

I have hours. My boarding pass agrees. Yet I'm rushing through the terminal with the urgency of a person whose name is being called over the speakers. By the way, who doesn't panic every time there is an announcement over the speakers? Even if the announcements have nothing to do with you, they get your full attention because they could have something to do with you. 

Getting out of the house has involved checking for the same four items multiple times. Phone, passport, wallet, ID. They are all there until you think about them again and need fresh evidence. Your ID can escape from a zipped pocket, so you have to make sure it is still there. 

Your travelling companion is walking at a normal pace. But you're part of the 3-hours-early team, so you have zero chill, and no intention to calm down until you are at the gate. You could go code red over absolutely nothing. And if there's a gate change? Worst-case scenario for anxious travelers. You enter full survival mode and won't breathe until you get to the correct gate that is on the other corner of the airport. Well, it's just a gate change, not the Hunger Games. You are at the correct airport and you will find it. You have plenty of time for this. 

Then, when you reach the gate, you finally check the time properly. There is so much time left that you can buy a coffee, drink it, stare at the empty cup, count the number of floor tiles at the coffee shop, and still have time to spare. You could walk around, but the confidence and reassurance that gives you the seat feels like an accomplishment. Besides, leaving it would mean admitting that the rush wasn't necessary.