Asklemmy

So, this is a question with a cultural and legal element. Legally speaking, it is possible in many U.S. states to be fired for no reason -- the employer does not need to explain themselves when asked for a cause[^1]. This is to say that it's perfectly legally possible in (many) U.S. states to be fired for a reason so petty as a customer complaint -- whether or not that was the official cause notwithstanding[^2].

With that being said, employers aren't compelled to fire their own employees in response to a customer complaint. From a management perspective, it's generally very inefficient to fire someone because you'll then have to cover their hours and find/train a replacement. For that reason alone, it's already rare in most industries for truly petty firings to happen. Unfortunately, this rule of thumb gets totally flipped in low-training industries whenever there's a surplus of bodies in the labor pool. As a manager, if you're able to replace a burnt-out and/or below-average worker by the end of the week, why wouldn't you roll those dice?

Even then, it's not exactly a daily occurance even in settings where these conditions are common... with one big exception. When it comes to businesses which serve "regulars" (e.g.: hotels, restaurants, grocery stores) there exists a certain type of individual who expects that their complaints will have the power to get people fired. This variety of power-starved person tends to exclusively patronize establishments where they feel taken seriously. Such establishments deliberately choose to indulge these sleazebags because they're potential "whales" -- people who, if handled correctly, will be worth much more money than the replacement cost of the staff they cause to be fired. These firings are basically performative in nature and have nothing at all to do with something the employee could have controlled.

[^1]: Protected classes are a whole other can of worms. For the purposes of this explainer, please just trust me when I say that the legal system is still able to protect protected classes without directly requiring paperwork from the employers themselves. The system would be significantly better at this job with a papertrail requirement, but the fact that it manages to work at all when employers can basically ghost employees is something worth noting.

[^2]: Another can of worms! As you may imagine, when giving a reason is optional, it is often (but not always) legally advantageous for employers to report petty firings as no-cause firings. It's all about CYA. For example, if they're doing something dicey like racial discrimination or retaliation against union organizers, an employer might go in the opposite direction and meticulously document dozens of petty reasons in excrutiating detail. This is usually what's happening when a service-worker employee is "written up" -- that information goes in a file to be used against them if they ever sue.