Translation:Sometimes, I think you need to know how to be selfish.
How do we know when to translate it as "we need to know," "one needs to know" or , as is here "you need to know." My answer was "we need to know;" marked incorrect of course. I also answered with "...an egotist," instead of "...selfish," so I don't know if that was the problem. It's a guessing game at this point.