Jerry Seinfeld once remarked that if one's going to kill oneself, the least one could do is to leave a note (this happened in the second-season episode 'The Phone Message'). I tend to agree with this. The note should not point fingers ("it was my wife's fault!"), but simply outline what was troubling the deceased and his reasons for doing the deed, along with some final wishes not expressed elsewhere. There is an even better way of doing it, which I will come to below.
I have little doubt in the rationality of many suicides. Certain variants have near-universal approval, in particular decisions by terminally ill individuals not to medicate or to be euthanized. Maybe some "diseases" affect the mind and are just as terminal as the diseases leaving physiological traces? If so, one cannot claim that suicides by seeminly healthy individuals are in error while simultaneously thinking the cases by the terminally ill are right. Once the decision to off onself is arrived at rationally - there is nothing anyone can say to change the situation for the better. No advice works.
This is not to suggest that one should not urge suicidal persons not to do it, because how can outsiders be certain that the decision was arrived at rationally? And maybe some sort of side-payment could be arranged in order to keep the suicidal person in this life. Even rational suicides are extremely tragic. The people left behind will very frequently and understandably feel in the abyss and so are apt to do all they can to prevent a loved one from committing suicide. I know I would.
Which leads to the following conclusion: If one's going to kill oneself, then yes, the least one should do is to follow the Seinfeldian wisdom and leave a note. Doing so and doing it well avoids very many painful and unanswered questions for those left wondering. But one could, if one is really intent on killing oneself, do one better by killing oneself, in a manner of speaking, by proxy - let circumstances do the work, but look up some of the socially most acceptable circumstances and get immersed in them.
By this, I mean that one should engage in some incredibly risky activity which has some nobility attached to it. Rock climbing, for instance, or volunteer work in risky areas. Call it a major life change. Those happen. The more daring the activity the better, for two reasons: (1) it increases the social benefits in case of survival, and (2) it increases the likelihood of death, which by definition is good for the individual who has rationally reached the conclusion that he should kill himself. Military activity can be socially acceptable, but society is wrong here - perhaps predictably so.
One might ask why not more suicides occur this way. Perhaps those suicides are committed by selfish people, or perhaps they are committed in fits of depression, possibly for irrational reasons. It is conceivable that many deaths from dangerous activities are actually suicides. Maybe the aforementioned military activity is one such venue, though I wish they would find something better in that case. The people close to those who pass away in this fashion may suspect that suicidal factors were part of the diseased individual's choice of activity. But at least in these cases there will remain the added sense of respect for the service the perished person rendered.