The lot of an airline passenger, 'normal pay for yourself class rather than tax-payer paid for your ticket class', is now becoming unbearable. Such simple things as luggage is making the whole affair beyond tolerance. And please don't just say, "obey the rules and all is OK". That is too simplistic. It is a customer service industry and all must make a profit, of course, but the base principles of service should not be neglected. The marketeers will no doubt disagree and the market rules, OK.
Just look down the list of airlines and their cabin bag regs. A couple of cm's here in width, a couple different there in length. A couple of kgs +/- here & there. It is a nightmare and it also occurs where it is the same type a/c, i.e. the same size internally. All baggage shops sell 'cabin size bags', but that is to true unless you take the smallest size. I heard, some years ago, of one lady who travelled from/to EMA. Problem was she went out with a LoCo and returned with BMI. BMI's cabin bag 5cm smaller in one dimension than the LoCo outbound. Bag removed and £25 charged for 'Hold baggage at the desk'. Madness, utter madness. At MAD they had a mettle template at the gate. It had open sides. The pax slipped their wheeled case into the template, but the wheel stick out of the side. The gate agent could not lift it straight out and wanted to charge for hold luggage. The student pax broke the wheels off the case in protest; in front of all the horrified pax. What a -ve advertisement.
Air rage starts on there ground. Why should an easy job be made difficult. By that I mean all the differences, which seem niggly & petty. There is no justification for a couple of m's difference. There is an ICAO standard. Use it. easy jet do, why not everyone else?