knowing or not knowing?

I would think that knowing everything they are likely or unlikely to get/have would make them more unhappy. I had the choice of being tested for the mutation for ovarian cancer and I chose not to have the test done because there is nothing I can do about it now and knowing would only make me unhappy and worrisome. This would impact my life negatively and would not help at all. The idea that they know the percentage of if they’ll have depression or a heart issue or anything else is scary and I think it would only make living harder to be honest. But on the other hand, knowing some things can help people to make choices in there lives to avoid them or to be safer in the long run. Like for me, I am able to get regular check ups for ovarian cancer and do some other little things to decrease my chances of getting it. 

Im wondering what everyone else thinks about this.