One thing I’ve never understood whilst waiting to board flights in an airport is people sitting down before they board an aircraft for 13 hours, or however long it is.
For as long as I can muster I try and walk around and stand up as long as possible.
Taking the stairs instead of all the elevators and escalators.
Then by the time you’re boarding, you can feel relief in sitting down knowing you can be comfortable for an extended period of time.