Brazil is quite a complicated place when it comes to bureaucracy; things move slower than they should, and it's one of the things that annoy people the most here.

Well, getting into a stranger's car is indeed dangerous, but it's natural for Brazilians to be welcoming and enjoy helping others. Perhaps this is the predominant characteristic of people here. Still, it's always good to be cautious. Despite most people being honest and charismatic, you can never really know when someone might have bad intentions behind a good deed. I guess this happens anywhere in the world, not just here.