I've used 23andMe, and it told me I have twice the risk of developing Alzheimer's disease when I'm older. Considering that I've lost a few family members to Alzheimer's, it worries the hell out of me. Regardless, this has triggered me to research a bit about the disease and ways of potentially reducing the risk.
It does make you anxious, but when you have that knowledge, you feel the need to do something about it.