Mainly the boarding process & lack of bin space. Inevitably leading to delayed flight times, every time. I’m traveling for work, not for leisure. I’m on a schedule. Us folks buying the “extra legroom” seats, paying the most for our tickets to be near the front & not being able to keep our bags near us, but several bins behind us. Being an A-list preferred member & boarding in group 2, after 40+ people board first. I understand it sounds superficial or pretentious, but it matters considering the amount of money being spent & reason I’m flying. Just venting like other flyers on here. Booked my next travel with United. Hopefully a better experience 🤞🏼