To Thine Own self be true

Do you ever wonder what is good and what is bad?. Is it a fair assumption, that anything approved by larger population is good or how about, anything that I should not be scared of doing, is good. But if fear of having to face someone's wrath or god's wrath, is what defines good and bad, then by definition good is fear and bad probably is brave. I know it doesn't sound right.
         We just assume something to be good coz' it meets the requirement and has majority approval. But i think Good and Bad are one and the same. Let me see if I can put this in simple words. Milk as it is, in its purest form is sweet and it lasts longer if you store it. But you leave it out in open, it becomes sour. The transformation, if you see, is simple yet unbelievable. One is good for you and the same milk in its latter stages, when sour, is bad for you. Now, if we talk in terms of equations (everyone has done some sort of math), milk is constant here so how can milk be good and bad. Alright, one more example. Rules and conditions are good. We learned from our parents, that following a pattern/routine is good. It will make life easier and organized. It was forcefully embedded into us so we don't waiver. But taking away free will/choice is making us mechanical. So free will is good here and Rules are bad?? Other side of the coin, free will without any direction or plan is aimless. We need some guidance and rules so we don't go overboard. So, is free will bad and rules are good now?? The person inclined with free will says its good and person with authority says rules and conditions are good.
         I think it's perspective. It's not about good and bad or god and evil. Definition of Good and Bad will change as things change. Do not compare it to something or some incident. Things that are bad at some point of time in our lives can be good at some other point of time. So in reality good can be bad and bad is not necessarily bad. It just not the right time. "to thine own self be true", It's all about intentions and if you are true to your intentions then rest is all noise. I hope i made sense in this whole thing. If not don't worry about it and sorry for making no sense. Trust me there will be a time and moment when this will make sense. Cheers to you.