What is your conspiracy theory?

Theories, Hypothesis, opinions, anything. What is something you're convinced of that people often laugh it off? What is your "hidden truth"? Please share evidence or references we can look up on

I'll start: bitcoin will be adopted by governments in the near future. Our vision on addictions' neurological dependency is highly equivocated (read the freedom model). Health professionals will be out of a job due do birth rates going downhill (logic).