Being able to think in 2 different languages helps your ability to multi-task.

Multi-tasking causes a lot of stress for many people. When you are fluent in more than 1 language, multi-tasking causes less stress and is easier. Though, I still don't recommend this from a productivity angle, there are times when we need the ability to do more than one thing at once, and it would be nice if it didn't stress us out in the process!