If Brazilians value any single trait, it’s optimism; it’s being able to solve problems. And if the problem can’t be fixed, just relax and forget about it. At the first signs of someone’s stress, a Brazilian often says Fique tranquilo. It has a very calming effect.
If the bus takes off just as you arrive to the bus stop, don’t worry. Fique tranquilo: There’ll be another one in ten minutes. And you can make friends while you wait. (source: www.dummies.com, networkplan.com.br)