As far as reasons against suicide:
(Note: I don't want to sound like a pro-lifer, but to argue this side of the argument, I would temporarily take that position)
1) (Only applies if you have someone that depends on you such as a child) It would be selfish to let someone that you brought into this world to go without a parent or parental figure.
2) Due to SI (survival instinct), you may have second thoughts, doubts, and things holding you back.
3) Life may get better and one may actually miss out potential future pleasure.
4) (Only applies if you believe in a religion that forbids or disapproves of suicide) If you religion has consequences for suicide, and you follow/believe said religion, then you may suffer in that religion's afterlife (hell, purgatory, or w/e).
5) Eventually you will still die (natural causes and other ways outside of suicide), but you only live once.
Reasons for suicide:
1) You are alone and likely going to be forever alone (this is a common, but very valid reason for ctb'ing and a lot of people ctb over being single).
2) Things aren't likely to get better, the same shit happens over and over, resulting in future pain and suffering. (Societal problems, personal problems, and things outside of one's control).
3) Getting old and bedridden, wasting away in a nursing facility is not a dignified or pleasant way to go. Dying young means you avoid old age and infirmity.
4) Having control over (which is essentially #3 but slightly different) when and how one passes is one of the most empowering and important freedom a human being has since no human ever consented to life but was rather the product of two other humans deciding to procreate.
5) (Opposite of the against suicide for #5) Since we're all going to die anyway, death is still death
Just fyi, I'm more ambivalent when it comes to others' choices, I'm just presenting both sides of the argument. As for me, personally I lean more towards ending pain and suffering and the choice to live or die.
