[msantos]

> I decided in this question to focus on what I regard as obstacles to enter on another countries or finding a job.

That's the wrong approach. In most countries you'll need a job before getting a visa, so focus on job market research beforehand, then check the visa obstacles.

Unless, of course, you don't need a job because you have (loads of) funds to apply for a entrepreneur kinda of visa.

If you have never lived outside your own country, I suggest you write down a list of questions you might have and then ask them around. You might have better changes to get them answered that way, instead of generic stuff. Immigration is highly subjective, by which I mean it depends a lot in people's particular circumstances as much as in foreign laws.