The problem with believing myths is this: you shut down life-changing opportunities or miss out on the full benefits of them. Take the example of mindfulness meditation. If you buy into the myth that this practice is passive, your active personality may assume it is not a good fit.
So, how do you best determine if an activity such as mindfulness meditation is for you? Do your research. Check it out. Get the facts. Gather information. Maybe even participate. Then, and only then, can you make an intelligent, informed decision.