Why I finally settled on charcoal was because... of all those people who accidentally die in their sleep every year without even noticing, it's called the "silent killer" because it's painless, odorless and you don't feel like you're suffocating. it's also easy and cheap, although I would recommend reading the huge methods thread on it. One thing I noticed from reading it the first time, is all the people who weren't ready to die yet. If you're not ready, and there's NO shame in that at all, then of course you're going to self sabotage every method you choose.
Another thing I noticed from that thread, is all the people who had never handled charcoal before and then assume it'll work perfectly at a time when they're maybe upset or stressed or under pressure. Practice until you feel comfortable, have a cookout. Get used to what is needed to get it lit and stay lit, so it burns evenly and and all the briqettes are ready at the same time, how long it takes to stop smoking (cos the smoke isn't what kills you), and how to transport it to your special place. Then there won't be any surprises and you'll be a happy dead person.
Another thing I noticed was that the people who came back and said their method failed, they didn't have any serious side effects. Personally, I'm buying 2 bags, if I wake up I'm trying again, lol. I can't believe I overlooked this method for so many years but... I guess I wasn't ready. *shrugs*