In five years I think I will still remember what I learned about the six scientific principles of psychology. These principles will stick with me because they can be applied to multiple aspects of life. For instance falsifiability will be helpful when pseudoscience is prevalent. When ads appear on television I will now know if they can be trusted or not. I've learned that many of these ads do not have replicated studies to back them. The ads also have a lot of reliance on anecdotes. These results can vary from person to person and do not guarantee the same results for everyone.
Another scientific principle that will come in handy would be correlation verse causation. Just because two things are correlated does not mean that one of the events causes another event. I think this will be helpful when making assumptions about either how people act or about certain situations. All of these scientific principles will be helpful in the future when dealing with the life experiences that are sure to come.