Depending on how the airport is arranged you can find yourself doing a lot of walking or standing around in not quite stationary queues. If you can manage to find somewhere to sit down where it isn't too noisy, it's fine, but often that's harder than you'd think, and you find your concentration is just continually broken by something or other that's going on or that you need to pay attention to.

Budget airlines and priority boarding are a particular bugbear of mine here. Most people pay for priority boarding just for the extra bag it allows you to take into the cabin. You end up with two thirds of the flight made up of people who have priority boarding. That's great, but there's only so much space in the overhead lockers, so you have everyone queuing up way before boarding starts to avoid having their cabin back checked into the hold at the gate.

The whole process is just... endlessly tedious and wearisome. I'd genuinely rather board a much slower form of transport, like a train, coach, or ferry (or even drive under some circumstances) than deal with being treated like cattle at an airport. The whole experience of airports, and getting to and from them, sucks.

In America, all the gates (I have been to) subject you to constant noise pollution in the form of announcements over the public address system.