Death is often viewed as the ultimate evil, and, in terms of utility, the ultimate negative outcome. However, I have always had a somewhat cavalier attitude towards my own mortality. This is my attempt to rationalize the two.
Selfish utilitarianism is, in my opinion, the most rational method of decision-making. By weighing one's choices against a variety of possible outcomes, one can come to decision that results in the best possible outcome. By quantifying (or simply relatively comparing) subjective measures such as pain and pleasure, it is possible to apply utilitarianism to any situation.
But when it comes to the issue of death, utilitarianism usually states that death (of yourself) has an extremely negative value, to discourage one from courting options that have higher probabilities of death with low rewards.
Why? Why is one's death an outcome to be avoided? Selfish utilitarianism states that suicide is preferable to a life of suffering (where future pleasure < 0, due to extreme suffering, or neurodegenerative disease), but apart from that scenario, there are very few reasons why selfish utilitarianism would advocate suicide, as suicide prevents all prospective gains.
All evidence points to the fact that selfish utilitarianism discourages suicide. However, my argument rests on the fact that one cannot tally the utility until after the event has occurred.
Especially in cases where the outcome is uncertain, one can only calculate predicted utilities, and usually utilitarians would choose the choice that results in the highest average utility. However, if one chooses a suboptimal average utility, then depending if one's actual outcome is greater or less than the optimal average utility, then one cannot or can regret one's decision respectively. One cannot regret one's decision before the event occurs but after the choice has been made, as the outcome is uncertain. Utilitarianism only provides guidelines for the most optimal choice; whether or not you get the best result is not dependent on taking the most optimal choice.
As one cannot regret a decision before the utility has been gained or lost, one cannot regret a future that has not yet come to pass; one may only regret choices that have already had their effects. And if the result of the decision is the cessation of consciousness, then one has no time to regret one's decision.
And that lies at the crux of the argument. If one has no time to regret one's decision, the decision is as good as if the decision had nothing to regret in the first place. Although death cuts off one's future, one cannot regret a future that does not happen.
Does it decrease overall utility? Yes. Can you regret this loss in utility? No.