Sadly I have carried one in the back of my head since I was a teen. It only surfaces when I really need to get more help than I am admitting to myself. Though I will have those random , "the world/my spouse/my family would be better off without me" thoughts from time to time.. It comes down to how I use self talk to get myself away from it becoming more serious and detailed.

I dont think its normal for society to have them in the back of their heads all the time.. I think it is normal for Bipolar II since the depressions can be so much thicker.