So the fairy godmother shows up. And she is lovely. And she has a wand with magic in it.
She tells you that you can have one wish, but that it cannot be a wish that applies only to you or your family. It must be a wish that is of benefit to the community or to the world at large. One thing you could change to make it better.
What would you choose?
Note: Although answering "world peace" is awfully cliched thanks to all of those Miss World and Miss Universe contestants, it is a perfectly wonderful answer.
I'm always wary of this question because of the 'take things too literary aspect' that is associated with genies. E.G., Wish for world peace and everyone loses the ability to speak, wish to be rich and you later get arrested for robbery.
Assuming this would not be the case, I would wish for an end to global warming and that our world no longer suffered from pollutants.
I asked my brother this very same question and he told me that he would wish to have another ten or so wishes. Then he could use the last wish to ask for more wishes. Quite greedy but undoubtedly a very sneaky tactic.
I myself think that I would wish for health so that I can do all the things I plan to do. I find that one should be satisfied with what he has, for if fortune comes too easily, it won't be as valuable. People are greedy by nature. And asking for something like world peace or equality is simply not realistic. Just look at the history of humankind, these things don't last because they go against the selection theory. People always wish for something better, and that is what motivates innovations.