I left Portugal in 2003 to work in the games industry. There were still plenty of jobs in Lisbon then and salaries were not so bad.
At the time I thought I would be away for a couple of years "just to get some experience".
I would love to go back to be closer to my family and old friends, to enjoy the weather the beaches and nice food, but as another expat told me, our jobs just do not exist in Lisbon.
Setting up a business is hard with the asinine tax system currently in place ( taxes are complicated, very high and if your business has zero profits it pays a special tax ), a culture of late payment by clients ( it is so common to have unpaid invoices that you can give these to your bank in exchange for a loan ), the absolute aversion to risk taking by most businesses, the ingrained idea that what is foreign is better and the implied notion that to win a contract you need connections to a politician or a civil servant.
I know a lot of professionals in knowledge based industries that have left, some with their entire families. In a recent poll, more than half of university students plan to leave the country.
At this rate Portugal will become mainly a touristic destination.