I will put my two cents worth in (yes, I still lurk about in here....this October I will be back in with an entry!). Our reasons probably don't make a lot of sense when compared with the experiences (and especially challenges and hardships) of others, so perhaps just taking the reasons on face value without comparison might be good
I study, and I love study, particularly research. Having lived in South Bay, CA for a couple of years I would look at Berkeley longingly never thinking I would go there. Fast forward 5 years and I am now about to graduate at Uni in Australia and am considering a PhD so for me, that dream that was as likely as unicorns, might just eventuate
Also, my hubby's career pre Australia was in Silicon Valley, and Australia is soooo far behind in that field (seriously doubt we will ever catch up sometimes) that if we ever returned, he may be able to return to the work he did before. Also, I experienced so much difference when I lived there that I have not been able to shake the longing to return. Australia is incredibly expensive, and the choices are limited compared to CA regarding goods and services. I kind of have to agree with the post above too...Australia CAN get dull...truly! It's pretty, it's hot, it's quaint...but it is a hell-of-a-long-way from anywhere, and there are some issues, culturally, under the surface that only Aussies really know about; they are an ugly side to our society...and they are not ever shown in the glossy, blue sky, gorgeous beach tourist commercials.
I read once, you get one life, try not to have regrets. I have lived half my life....given the choice (or rather the chance), I would like to have a different one for the second half left.
Q