Before we decide how 'selfish' a person is to commit suicide, please consider the following....
A person that is clinically depressed, as can happen following redundancy, divorce or other major traumas in a person's life, does not think in the same way that a healthy person does.
There is an expression used by Coronoer (in the USA, Medical Examiner) that sums it up, "Took their own life, whilst the balance of his/her mind was disturbed." What this means is that the chemical balance of our brain becomes imbalanced, when we are depressed. If this is not recognised in time, it can lead to severe depression and suicide.
For example, 18 months ago an well know English photographer took his own life. He had been been known to all as a cheerful and respectable man all his life. He was given some medication for a particular condition (I forget what) and a side effect of these pills was to make him depressed. Within six weeks of taking them - he died.
When a person is feeling 'low' or 'bad' they do not immediately realise that they are depressed. It can take many months for depression to be identified. Those that are used to taking decisions and being respected are likely to feel a serious change in their lives when that work ends suddenly. This may lead to a chemical imbalance.
Those that have such an imbalance DO NOT REALISE that they are loved and appreciated in the way that they are. It is well documented that they THINK that their family will be better off without them. They THINK that no one loves them - even though people give them love all the time.
There are some similarities with the eating disorder Bulimia Nervosa. The person THINKS that they are fat, even though they are thin. When they look in the mirror, they see something different to your or I because ... the balance of their mind is distrubed.
Please note that I am not a medical doctor but have known many families with people who have experiened depression (both light and heavy) as well as those families where people have killed themselves as a result. This is due to some (non-religious) charity work that I do in my spare time.
Mental difficulties are something that we know little about and the old fashioned, "Pull yourself together" is no longer the correct approach.
May I suggest that the next time you hear of a person taking their own life, you respond with a little more understanding.