Psychology has been an excellent source of insight into the realm of the human brain. Above all, the information I found most useful and will always take with me was the first unit we covered. The section that stood out and that I put to use almost daily are the principles of scientific reasoning.
As I evaluate situations in my daily life I put these principles to work to ensure I see the issue as it truly is and don't let the symptoms and claims cloud my reasoning.
Extraordinary claims is the first rule I live by and that will stay with me. The reason that this sticks out in my mind is because too often I'm told stories and facts that seem rather far fetched. I no longer take these claims as fact with the scientific principles in use. Occam's razor also goes along with extraordinary claims because I now look for the most simple explanation over all the hype, unless there is the extraordinary evidence to support the claim.
I am a now more rationally thinking person because I took this course. After I learned these principles to think scientifically, I make better decisions and give better advice as well.