There are two emotions you are sure to feel in airports: anxiety and boredom.
And most of the time you have the option of which one to feel. On departing flights that is almost always the case and here's how:
i.) You can show up early and be bored
ii.) You can try to time it so you don't have to wait too long and be anxious.
I choose boredom every time. Most professional travelers choose boredom.
Airports work in cycles. Planes depart around the same time. Hundreds even thousands of people depart on dozens of planes around 6am, then 8am, 10, noon, etc. Generally speaking that is true.
Therefore airports go from busy to empty every couple of hours.
If you show up two hours and 15 minutes before your flight you are likely to find quiet short lines. If you show up one hour before your flight you will find long lines full of angry and anxious people.
Delays happen. You will miss a connecting flight now and then. This cannot be predicted or avoided. When it does you can choose to accept it or not.
If you do accept the fact that you are going to be delayed, you will be bored waiting.
If you choose to enter the arena of carnage that so many travelers choose ... and try to optimize your delay at the expense of everyone else, you will get angry and then anxious.
As I've said before, traveling via airports has asymmetric results. Best case, you arrive on time. Worst case, you will be delayed for hours or days. No flights suddenly arrive four hours early. They only get delayed.