I guess for me it has always come down to my mental state, you get depressed, every day feels like hell & all you want to do is end it, now i often forget between episodes of depression (probably my mind not wanting to remember) how the whole process, for me at least goes, i can spend months/year or more depressed wanting nothing but the end Now & frustrated that i just cannot let go, then i get back to the point i did a 7/8mths ago where i remember that it is always this way, the fighting with myself to give up when stupid in me still clings to hope, but thats fine as for me it is just part of the process. Now i have got to the easy bit, where there is no Si just a absolute need, the type that intrudes constantly into your thoughts, taunting you to just get it done (by now the depression doesn't help by sucking the life out of me when i still have shit to sort)
I understand that for a lot of you this is a rational life choice (if i have worded that wrong no offence was intended) in the face of a world/society that is truly fucked up & you do not want to live in.
I just come at it from a purely screwed up mental health, lifetime of recurrent depression point, so i think what tips us over the edge so to speak is going to be different for everybody.