In this case all jobs are equally bad (and equally good,) therefore the words "best job," or even the words "good job" or "bad job" can have no meaningful interpretation.

No, it could be the case that someone is unhappy whenever they're working. For someone like that, the best job is one that pays a lot for a small amount of work. The lower the pay rate, the worse the job.

I think that's a meaningful interpretation. In fact, I think this situation is pretty common among people in the world.

Touché. Although I think bringing higher reasoning into what was clearly a bit of pleasingly pointless formal logic pedantry is a bit unfair. Like taking an assault rifle to a waterfight.