So I have a conundrum. Imagine that Omega comes to you and offers you two choices:
First choice: You get a moment of moderate pain, let's say a slap and then another slap, so that your face hurts for a couple of minutes with some anguish. Now after that pain has faded and you still have the memory of it, Omega measures your discomfort and gives you exactly the amount of money that gives enough joy to compensate the pain and then a cent. By construction, the utility of this choice is one cent.
Second choice: Omega inflicts on you hell for a finite amount of time. Your worst fears all come true, you are unable to distinguish between reality and this hell, the most painful sensations you will experience. After this finite amount of time is over, Omega deletes all memory of it and gives you essentially unlimited monetary funds but still, this experience does not quite compensate for the previously experienced hell if you would remember it. By construction, the expected value of this choice is negative.[1]
If we go by expected value, the first choice is obviously better. Of course Omega forces you to take one choice or you will just get hell forever, we want our thought experiment to work. But if we go by the decision procedure to choose the option in which our future self will feel best, the second choice seems better. I have not yet found a satisfying solution to this apparent paradox. Essentially, how does a rational actor deal with discomfort to get to a pleasurable experience?
[1] I realize that this might be a weak point of my argument. Do we just simply add up positive and negative utilons to get our expected value? Or do we already take into consideration the process of forgetting the pain? Maybe therein lies a solution to this paradox.
How could one know with any certainty what's better for them (in the murkier cases)? Alternatively, if you do have a process that allows you to learn what's better to you, you should claim that you can also help others to apply that process in order to figure out what's better to them (which may be a different thing than what the process says about you).
You can of course decide what to do, but having ability to implement your own decisions is separate from having ability to find decisions that are reliably correct, from knowing that the decisions you make are clearly right or pursuing what in fact matters the most.