- The restaurant is a near-monopoly at which I have to either eat at or go hungry.
- The reason I "don't like my meal", as you say, is because it was served to me multiple days late, during which time I was unable to leave and re-enter the restaurant without having to pay again (and this restaurant charges a premium).
- When I pay for food at the restaurant, I often receive an empty plate instead. The restaurant refers to this as my "not liking my meal", and chalks it up to personal preference unless I raise a stink.
- The restaurant is somewhere I am forced to eat by my employer, and my employer will not refund me when they fail to provide food.
- The restaurant has a reputation for being mismanaged and implementing policies that torment patrons--sometimes by physically beating them.
- The restaurant has slowly but surely increased prices while visibly decreasing portion sizes.
And so on. For a lot of people "just don't fly" doesn't work (people with overseas family or travel for work). And for those same people, mega-airlines like United are often the only feasible choice or one of a very few equivalently-shitty choices.
Also, complaining by email decreases (doesn't eliminate, but decreases) the annoyance caused by antagonizing an in-person employee of the airline with your grievances. The person whose day you might ruin by interrupting them is not the problem--their employer is--but it's very hard for many people to refrain from acting as if that person is responsible when they confront someone. The person whose job it is to read the complaint emails probably isn't having a great time either, but at least they can (hopefully) take a smoke break if they need to.
If a flight delay causes me to miss a connection, then I paid for a service (getting me from location A to location B by a certain time) that I did not actually get. Same if the Wi-Fi is out of service.
There is no implicit promise at a restaurant that you'll like your dinner.
It's more akin to an ingredient being missing or something being burnt. It's not like OP is making complaints like "the seats were uncomfortable" -- parts of the service were objectively missing.
- The restaurant is a near-monopoly at which I have to either eat at or go hungry.
- The reason I "don't like my meal", as you say, is because it was served to me multiple days late, during which time I was unable to leave and re-enter the restaurant without having to pay again (and this restaurant charges a premium).
- When I pay for food at the restaurant, I often receive an empty plate instead. The restaurant refers to this as my "not liking my meal", and chalks it up to personal preference unless I raise a stink.
- The restaurant is somewhere I am forced to eat by my employer, and my employer will not refund me when they fail to provide food.
- The restaurant has a reputation for being mismanaged and implementing policies that torment patrons--sometimes by physically beating them.
- The restaurant has slowly but surely increased prices while visibly decreasing portion sizes.
And so on. For a lot of people "just don't fly" doesn't work (people with overseas family or travel for work). And for those same people, mega-airlines like United are often the only feasible choice or one of a very few equivalently-shitty choices.
Also, complaining by email decreases (doesn't eliminate, but decreases) the annoyance caused by antagonizing an in-person employee of the airline with your grievances. The person whose day you might ruin by interrupting them is not the problem--their employer is--but it's very hard for many people to refrain from acting as if that person is responsible when they confront someone. The person whose job it is to read the complaint emails probably isn't having a great time either, but at least they can (hopefully) take a smoke break if they need to.