To thine own self be true.
We all know the above quote from Shakespeare. However, a quote that I even believe in more, who's author's name escapes me, is: "A fight you will have your entire life is not to let this world change you for the worse into someone you are not."
Quite honestly, this is why my dogs meant so much to me. They helped me to get back to the person I was before I let this world change me for the worse, which lasted a couple of decades.
A gal that I worked with at a corporation in Green Bay was going through a very negative experience, as her grandmother who raised her had passed away. A couple of days after the funeral her fiance left her without any warning.
I could see she was understandably devastated. I told her, "If there is any advice I can give you, it is not to let what happened harden your heart and make you a colder person. Learn from it, be wiser by it, but don't let it change you in a negative way. Because then the experience wins and you lose."
Not letting the world change you in a negative way is a fight you will have your entire life. Believe me, it is a fight worth winning.