Life has no meaning. Due to that the only thing that really matters is the quality of the journey. Do you enjoy the Dance/Game of life. If most of the time Life is shitty for you (High amounts of suffering), even if nothing terrible really happens. You're probably better off dead. Why would you like to experience a shitty time?
Possible counterarguments – answers Not everybody feel more suffering than joy in their life – It's true, but many do. I would assume > 10%. Many of these people choose to live only due to fear of death, or to serve ideologies, religions or other spooks. They are being used by the system just like animals that are bred for their meat. It doesn't mean their life worth experiencing.
Even if it's rational to commit suicide, it's not easy or sometimes even possible, Survival instinct is a bitch – I agree, My argument only says that's the "rational" thing to do, the one that makes sense. Not that's it's easy or always possible.
Some people live for other people – Agreed again, if you have dependents (like small children) maybe it's better you won't kill yourself and leave them alone. Your friends/parents/wife are also a reasonable reason, but weaker IMO - if they really love you they should understand that death might be better for you.
