It's like bananas said,
it is not necessarily the a/c itself, which ads to the problem, it's not to have an alternate at every tree, weather phenomena much more severe after an 8 to 10h flight with no 2 hrs of extra fuel and ATC units that are not necessarily in your favor but actually working against you.
You'll be surprised how isolated your destination can be in a densely populated country sometimes.
I'd strongly recommend that you have flown your a.. off in short/med haul before you try the, share enjoyable, demands of real long haul you might not go to a certain area or destination for two years
and other challenges.
Although I strongly recommend it with the right amount of experience, never get's boring.