Is it better to know everything or stay ignorant about some things?

By knowing everything, I mean knowing facts.

Knowing everything can help you plan better. For instance, you could avoid buying an unreliable car if you know the car model’s reviews and ratings.

However, there are times when knowing everything could be harmful. For instance, knowing that everyone else in your class studies virtually 24/7 might prompt you to do the same. That could easily lead to burn out. Another example would be knowing a dark secret about someone/something you admire. As Mark Twain mentioned once in a poem (I think it was a poem), the joys of looking at a river’s beauty are gone when you realize that many of the river’s features actually pose a hazard to steamboat captains.

So, what do you think?