I've definitely had cases where the manager (and on lots of cases, the CEO) tried to "turn those conversation around" and bullshit me.
The thing they wanted me to do was maximum priority, but there was also some other totally unpredictable thing (often support related) that I also had to take care of. The higher-up was 100% sure it wasn't a real problem and assumed I was exaggerating the situation.
The solution to the problem of lack of trust is of course to convince them, or to leave. If you can't make changes that increase your productivity, you'll become stressed and burned out, and will still not be able to do enough. It is a decision they made.
If you're doing something you think is important ("other totally unpredictable thing (often support related)") at work and your boss says they think it isn't important ("The higher-up was 100% sure it wasn't a real problem and assumed I was exaggerating the situation.") then I would assume your boss is right and you are wrong and act accordingly (start ignoring or delaying dealing with these support-related things when you are busy with the "higher priority" work). Either it will turn out your boss was right and it won't be a big deal, or it will turn out your boss was wrong, and it will be clear to everyone, and before you know it a big pronouncement will come down from up high saying that that "unimportant" thing actually is very important.
The previous CEO of the story wasn't wrong about what's important at all. Only about how much time it takes. He considered everything important and maximum priority, but didn't believe the "previous thing" was taking 80% of the time of the team. I couldn't tell the team to "drop the previous task" like the other post suggested: it was also maximum priority.
"Important" and "Takes too much time" are very different.
He didn't think it was important to put in the extra time then. He felt adequate results could be achieved with less time, and that the extra time to make sure quality and completeness was up to some standard was unnecessary.
So, try it. See how well you can do in 0.8 times the time. Probably not as well, but maybe still adequate for the boss's standards, or maybe not. Either way the impasse is solved, as both you and your boss will see exactly what can in fact be done in 0.8 the time.
The thing they wanted me to do was maximum priority, but there was also some other totally unpredictable thing (often support related) that I also had to take care of. The higher-up was 100% sure it wasn't a real problem and assumed I was exaggerating the situation.
The solution to the problem of lack of trust is of course to convince them, or to leave. If you can't make changes that increase your productivity, you'll become stressed and burned out, and will still not be able to do enough. It is a decision they made.