I agree with your second post Ogrilla, but there are some things in the first that I find weird.
If you commit suicide, you're doing the world a favor, you're doing humanity a favor
Why is this? Something really important to remember in life is that you can never be sure exactly what will happen next. Never. One person alone can do extremely much good for the world, as well as bad. That's why you can never know if you are doing anyone a favor if you kill yourself, maybe if you didn't you would be the one to save humanity from a space invasion?
I'd guess your argument is that the world is overcrowded or something along those lines, the world would be better of with one less depressed brat to care for. What difference will one person killing himself do? None. It won't help the starving people in Africa. Most likely it will have no effect on society at all. There will probably be a few mourning people left, and that's it. One person can do much good, or much bad. You can say that killing yourself may do the world a favor, but not that it
will do the world a favor. You never know.
There is honestly no good reason to want to live on in the memories of your friends, family, co-workers, etc. It's a foolish thing to strive for since you'll have no way of appreciating it.
This one I just disagree with. Most people wants to be remembered, in a good way. Even though they know they can't appreciate it. I don't think that's foolish, I think it's natural. If people rejoice when you die, it means you've been a jerk in life. Most people doesn't want to be a jerk. I know I don't. I know some people think it's cool be be cold and cynical, but seriously; You don't care if your mother cries in your funeral or not?
I can't imagine why someone would want someone else to continue living, but that's just me.
This one beats me. Isn't there anyone that you would like to stay alive? That girl you've been dating lately, don't you care if she dies? There's a pretty simple reason for people to want someone else to continue living: They like them, they enjoy spending time with them. If you enjoy beeing with someone, you would obviously be sad if you couldn't be with them. I don't understand how you can't imagine that. Makes perfect sense to me.