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The first option is hardly feasible. If you just keep banging your head against the wall, the chance of death is minimal. At most, you might just get a bump on your head. If you continue this for a very long time, you still won't die – you'll end up in intensive care, and then, if you're unlucky, in a mental hospital.
The second option is more appealing. You could break your neck in a fall. But again, if you prefer to just sit down and hit something, aim for a corner.
The chance of an ordinary person killing a dragon is very small, and even killing a bull is problematic. A hundred knights would simply trample such a madman.
Jump onto the rocks? Now that's better. And it would be truly wonderful if thousands of people saw your splattered corpse. Maybe someone will vomit, someone will have a heart attack. Yes, dying can be fun.
Sell your life? That doesn't lead to death; it's just ordinary, boring slavery.
Shoot yourself. Not very interesting – it's too quick.
Although, if you go to your boss's house and splatter your brains all over the place with a shotgun, that could work too.
I'll skip the next two options; they're silly.
Defile the world before death? You can only do that to individual people. But! If you have money, you can organize a terrorist attack, and that would be a lot of fun! Play a real-life Counter-Strike with the pros! Isn't that cool?
At the end of the world? Well, Vikh is right – the main thing is that you won't be the only one kicking the bucket; everyone will!
Saving the world from the end of the world is impossible; that's what the end of the world is.
The rest is also silly, but the only thing is, killer bees are not poisonous.