"I can quit one of my night jobs" makes no sense

It's a funny joke, I get it, but when you think about it, it's not quite as polished as many of the other jokes.

Let's think about it - 'ONE' of my night jobs makes it minimum of three. If it was two, then it would not be 'one of' but 'the other' or something like that.

But 'three night jobs' is not necessarily any or much worse than 'one night job', because there are limited hours at any given night, so what's the difference if you work, let's say nine hours per night at ONE job..

(of course without defining 'night', we can't know how many hours we even have available, and it's weird that no one can seem to define these basic words congruently and accurately, everyone has an OPINION of what 'night' means, but it has never been 'scientifically defined')

..or three hours in three separate jobs?

What's the difference between working one 9-hour shift or three 3-hour shifts, except the hassle of coming back home and changing clothes and whatnot?

It's not necessarily harder to work one long shift than to work three short shifts. In fact, I'd reckon it's psychologically more interesting to not have to stare at the same cubicle wall or factory floor for 9 hours, but get to change to another one every 3 hours. It refreshes your mind a bit to change locations.

So as a joke, it doesn't really work, because it doesn't REALLY make it clear how three night jobs would be ANY more stressful/difficult/hard work than one long night shift.

Because it's the same hours, possibly same or at least fluctuating physical or mental workload, and some of the night jobs might be very easy and relaxing, even if one or two of them are more demanding, it makes no difference how MANY JOBS there are, only how many HOURS there are and how HARD WORK it is.

Also, thinking even further, quitting one of the jobs doesn't mean she has more free time necessarily. (I am so tempted to go full Benny Hill on this and say 'necescellery')

Now that she quits one 3-hour shift, for example, maybe the other job's boss hears of this and demands she does a 6-hour shift now instead of the previous 3-hour shift, so she will still work the same amount, probably.

She should just make it only one job but do it 6 hours, then she would still have more free time.

In any case, thinking about comedies and jokes and seeing how they make no sense might not be wise, but I am only thinking about this one, because it doesn't REALLY WORK as a joke. If it did, I would leave it alone.