I don't get stressed AT the airport. I get insanely stressed BEFORE I get to the airport.
Pack light as possible. We tend to try and keep it to only the most basic luggage size which will fit under the seat in front of you. No fight for over head lockers. People always take far too much stuff on holiday - even me when packing light. DH and DS are much better than me at taking only exactly what they need. No we don't repeat and no we don't wash usually. We roll not fold. And yes we have space to bring stuff back. This is where the stress is for me tbh but honestly it's worth it because you also have less to lugg about when you get there too.
It's all in the organisation.
Once at the airport I'm fine.
We tend to arrive very early. At LEAST three hours before. This takes a lot of the stress out of it.
Security we have down to an art. Everything packed strategically into easy to access cubes. So all the stuff they might pull out is right at the top of the bag.
Coats and boots and belts all sorted ready to go into the tray before we get to the tray. We don't get grumpy at the people who can't work out security. We are always super nice to staff even if they are grumpy - this one definitely eases tension and helps. It never tires to play a mental game before you get there of which group is going to make a spectacular drama of it. The most consistent group on this is always the hen do with women in curlers going through security, with a thousand hairdressers and house sized make up bags. That's the group you don't want to get stuck behind!
We also aren't adverse to getting fast track. Though tbh there's been times at Manchester airport it's been a waste of money. It's my home airport and honestly I don't recognise the comments about it being awful. You clearly have not been to the dreadful airports.
That said I absolutely loathe Schiphol with a passion which sucks because I have a Dutch friend and if I never have to go through Heathrow again it will be a good thing (BA lost us at terminal 5 once claiming we didn't board a plane on their system which supposedly tracks you around the airport and then cancelled our return flight as a result. This was fun when we found out at the airport for our return flight. Thanks BA). As a rule smaller airports are so much better even if they are shit once you are past security.
But the worst one we've had was a dreadful experience at Brussels Charleroi last year on our return too. The airport was queuing out the door to get into the building never mind get through security. It was hot, the crowd were pushing and it was standing room only. If we hadn't have turned up 3hrs early (and we were three hours early) we wouldn't have made it through in time. This is BEFORE the fingerprinting too. The airport is basically too small for the capacity it's processing and this is acknowledged and they are in the process of making it bigger. There's other airports which you can use as a viable alternative for a bit more money.
This is why I think the two hour recommendation isnt long enough tbh. All it does is mean you are in a rush and panicking about time. It's stupid. Give yourself longer at the airport with hand luggage only for short haul and it makes it a lot easier. It takes a lot of the stress out the process. Save the luggage for long haul. You can sit down and get something to eat without worrying about how long it will take. I'd rather just wait a little longer airside once you are clear of security.
We had long delays before and that's just boring and airports either run out of food or close. So we make a habit of trying to take an empty bottle with us if we can. Lots of airports have refill stations now and it saves a fortune too.
Then when at the gate we wait for the queue to go down rather than standing for ages and then waiting for everyone to faff. We've only got underseat luggage so it's fine and we can get on super quick when the onboard crew are starting to get grumpy at people for taking too long.
Tbh the flight itself and how irritating the passengers are is almost always down to your destination. Fly to Scandinavia and they are a dream. Fly to southern Europe and you have more issues. Fly to Albania and brace yourself. Don't fly to Spain in the peak of summer and expect it to be fun. US immigration are always arseholes. Manchester airport immigration were always an absolute delight and super friendly on return but we go through the machine now as DS is older. Genuinely lovely. Unlike the miserable gits at Heathrow.
I have to say I now enjoy watching the dramas of other people at the airport. It can be entertaining. Instead of getting annoyed at it I'm now just amused. I know what I'm doing and I'm in control and the idiots don't really effect me - the key to this is having plenty of time though.