"money can't buy you happiness" is a bit of a cliché. Philosophers have been saying it for thousands of years and it is embodied in the message of half of the movies I have ever seen. Recently happiness studies have been reaching the same conclusion. Money does buy happiness but only untill your income reaches a relatively modest level (about $10 000 per person per year I think, of course this all my blogging takes place in America) but then levels off dramatically. The message is clear, "tax the rich! They won't miss the money". Of course you could respond in a different way, "Most Americans are at that level already, top up the incomes of the poor to that level then leave the rich alone" which is not the same thing.
But I digress; the message of all those books and movies is that you should try to do the things you love, friends, family and love are super important and that achieving something can be very satisfying. To put the last point a little differently: Earning $50 000 is better than being given $50 000 and it's even better if you earned it doing something you like doing. This is not controversial, but underpins the attitudes of many on "the right", that making your own life is a good way to live a happy/fulfilling life and should be encouraged. It isn't surprising that happiness research finds that the unemployed are particularly miserable (even after adjusting for levels of consumption).
This is one reason why high employment rates are good, but it would also be good (and you knew this is where I was going) if we had opportunities to do things we (more or less) like. A really good way to do this is to have open immigration. America is a good place for academics; Italy is probably a good place for aspiring opera singers and Brazil is a good place for plastic surgeons (as far as I know).
If we are keen on self actualization (and who isn't?) then we should take these benefits of immigration seriously.